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NCERT Solutions for Class 5 Maths Chapter 6 the Dairy Farm (PDF) – 2027

NCERT Solutions for Class 5 Maths Chapter 6 the Dairy Farm – step-by-step answers to every exercise and in-text question of the chapter, as per the latest NCERT syllabus for 2027. Read them online or download the free question-answer PDF.

Chapter 6 of Math Mela is the longest chapter in the book, and it is all about multiplication. Daljeet Kaur’s butter packets, a family’s kitchen waste, a dairy cooperative with 268 villagers and a king who rewards three ministers with gold coins teach one big idea: there is never only one way to multiply. You can change the order, double and halve, jump to the nearest multiple, or break a number into its place values — and every road ends at the same product.

NCERT Solutions for Class 5 Maths Chapter 6 the Dairy Farm PDF

All the answers are on this page below. The PDF also explains every answer – why it is right and how to check it – so download it for revision.

PDFChapterDownload
Solutions PDF (English medium)The Dairy FarmView PDF
Solutions PDF (Hindi medium)दुग्धशाला (डेयरी फार्म)View PDF

NCERT Solutions for Class 5 Maths Chapter 6 the Dairy Farm – Questions and Answers

All 95 questions of the chapter (textbook pages 70 – 91) are answered below, in the order of the book – in-text questions, activities and the end-of-chapter exercises. Each answer is written the way you would write it in the exam.

Let Us Think — Pages 70–71Shape puzzles, butter milk pouches, Which number am I?, Make your own numbers

Let Us Think
Q1The given shapes stand for numbers between 1 and 24. The same shape denotes the same number across all problems. Find the numbers hiding in all the shapes.
a)×=b)×=c)×=d)×=e)×=f)×=×
The six shape problems printed on page 70. The same shape always stands for the same number.
Answer

One set of numbers that works: green pentagon = 1, orange diamond = 2, pink circle = 3, blue rectangle = 4, yellow parallelogram = 6, purple triangle = 12, white shape = 16, blue half-circle = 18.

ShapeNumberCheck
Green pentagon1(d) 2 × 1 = 2
Orange diamond2(c) 6 × 2 = 12
Pink circle3(a) 4 × 3 = 12
Blue rectangle4(b) 4 × 4 = 16
Yellow parallelogram6(e) 6 × 3 = 18
Purple triangle12(f) 6 × 12 = 72
White shape16(b) 4 × 4 = 16
Blue half-circle18(f) 18 × 4 = 72
Q2Place the digits 2, 5, and 3 appropriately to get a product close to 100. Share your reasoning in class.
Answer

Put 53 in the two-digit box and 2 in the one-digit box: 53 × 2 = 106. That is the closest you can get to 100.

Reason: With the small digit 2 as the multiplier the product stays near 100, and 53 is the two-digit number closest to 50 (50 × 2 = 100).

53 × 2
Step 1. 50 × 2 = 100
Step 2. 3 × 2 = 6
Step 3. 100 + 6 = 106
Q3A dairy has packed butter milk pouches in the following manner. Find the number of pouches kept in each arrangement. One is done for you.
Figure
The four arrangements of butter milk pouches printed on pages 70–71. The first one is done in the book.
Answer

All four arrangements hold 60 pouches. Only the way they are grouped changes.

30 × 2 = 60
20 × 3 = 60
6 × 10 = 60
5 × 12 = 60
Q4What other groups can you make? (with the butter milk pouches)
Answer

You can make twelve different groupings of 60 pouches. Every pair of numbers that multiplies to 60 gives one.

Number of groupsGroup sizeTotal
16060
23060
32060
41560
51260
61060
10660
12560
15460
20360
30260
60160
Q5Which number am I? I am a two-digit number. Find me with the help of the following clues. (a) I am greater than 8. (b) I am not a multiple of 4. (c) I am a multiple of 9. (d) I am an odd number. (e) I am not a multiple of 11. (f) I am less than 50. (g) My ones digit is even. (h) My tens digit is odd.
Answer

The number is 18.

Multiples of 9 below 50: 18, 27, 36, 45
Ones digit even → 18, 36
Not a multiple of 4 → 18
Q6Did you use all the clues to find the number? Which clues did not help you in finding the number?
Answer

No. Clues (a), (d) and (e) never help, and clue (h) adds nothing once (c), (f), (g) and (b) have left only 18.

  • (a) Every two-digit number is already greater than 8.
  • (d) It cannot be used: it says the number is odd, but clue (g) says the ones digit is even.
  • (e) The only two-digit number that is a multiple of both 9 and 11 is 99, and clue (f) already removes it.
  • (h) After (c), (f), (g) and (b) only 18 is left, so it removes nothing more.
Q7Make your own numbers. Choose any two numbers and one operation from the grid. Try to make all the numbers between 0 and 20. For example, 2 can be formed as 4 – 2. Could you make all the numbers?
100255102361243−×+÷
The number grid and the four operation cards printed on page 71.
Answer

You can make every number from 1 to 20 except 19. The number 0 cannot be made either. So 19 numbers out of 21 are possible.

NumberOne wayNumberOne way
0not possible1136 − 25
13 − 2124 × 3
24 − 2133 + 10
35 − 2144 + 10
412 ÷ 3155 + 10
53 + 2164 + 12
62 × 3175 + 12
75 + 21836 ÷ 2
84 × 219not possible
936 ÷ 4205 × 4
1012 − 2
Q8Which numbers could you not make? Is it possible to make these numbers using three numbers? You can use two operations, if needed.
Answer

The numbers you could not make with two grid numbers are 0 and 19. With three numbers and two operations, both become easy.

0 = 5 − 3 − 2
Step 1. 5 − 3 = 2
Step 2. 2 − 2 = 0

19 = 12 + 10 − 3
Step 1. 12 + 10 = 22
Step 2. 22 − 3 = 19
Q9Which numbers between 0–20 can you get in more than one way?
Answer

Most of them. 0 and 19 cannot be made at all, and 11, 16, 17 and 18 can be made in only one way each. Every other number from 1 to 20 can be made in two or more ways.

NumberWays to make it
13 − 2, 5 − 4, 4 − 3
24 − 2, 5 − 3, 12 − 10, 10 ÷ 5, 4 ÷ 2
35 − 2, 36 ÷ 12, 12 ÷ 4
412 ÷ 3, 100 ÷ 25
53 + 2, 25 ÷ 5, 10 − 5, 10 ÷ 2
64 + 2, 2 × 3, 10 − 4, 12 ÷ 2
75 + 2, 3 + 4, 12 − 5, 10 − 3
85 + 3, 10 − 2, 4 × 2, 12 − 4
912 − 3, 36 ÷ 4, 4 + 5
1012 − 2, 100 ÷ 10, 5 × 2
1136 − 25 only
122 + 10, 4 × 3, 36 ÷ 3
133 + 10, 25 − 12
142 + 12, 4 + 10
155 + 10, 3 + 12, 25 − 10, 5 × 3
164 + 12 only
175 + 12 only
1836 ÷ 2 only
205 × 4, 25 − 5, 100 ÷ 5, 2 × 10

Order of Numbers in Multiplication — Page 72Daljeet Kaur arranges the butter packets

Math Talk
Q1Daljeet Kaur runs a milk processing unit. She has arranged the butter packets in the following ways. Find the number of butter packets in each case. What pattern do you notice (or observe)? Discuss in class.
(a) 2 × 3 and 3 × 2
(b) 5 × 8 and 8 × 5
6 groups of 13: 6 × 13 and 13 × 6
(e) 10 × 5 and 5 × 10
(f) 8 × 20 and 20 × 8
(g) 12 × 9 and 9 × 12
Answer

Both arrangements in every pair hold the same number of packets. Here are all the answers.

CaseFirst waySecond wayPackets
(a)2 × 33 × 26
(b)5 × 88 × 540
6 groups of 136 × 1313 × 678
(e)10 × 55 × 1050
(f)8 × 2020 × 8160
(g)12 × 99 × 12108

The pattern: the number of groups and the group size are swapped, but the total never changes.

Q2What is 9 × 0? 0 × 9? Is this true for the product of any two numbers? Discuss in class.
Answer

9 × 0 = 0 and 0 × 9 = 0. Yes, this is true for any two numbers: changing the order does not change the product, and any number multiplied by 0, in either order, gives 0.

9 × 0 = 0
0 × 9 = 0
So 9 × 0 = 0 × 9 ✓

Patterns in Multiplication by 10s and 100s — Pages 72–74Filling the place value tables

Let Us Do
Q1Let us revise multiplication by 10s and 100s. a) 4 × 10 = ___ b) 20 × 10 = ___ c) 10 × 40 = ___ d) 10 × 10 = 100 e) 20 × 50 = ___ f) 80 × 10 = ___ g) 3 × 100 = 100 × 3 = 300 h) 8 × 100 = ___ = ___ i) 10 × 100 = ___ = ___
Answer

Here are all the answers.

QuestionAnswerThink of it as
a) 4 × 10404 tens
b) 20 × 1020020 tens
c) 10 × 4040040 tens
d) 10 × 1010010 tens (given)
e) 20 × 501,0002 × 5 × 10 × 10 = 10 × 100
f) 80 × 1080080 tens
g) 3 × 100100 × 3 = 3003 hundreds (given)
h) 8 × 100100 × 8 = 8008 hundreds
i) 10 × 100100 × 10 = 1,00010 hundreds
Q2Find answers to the following questions. 100 × 90 = __,000; 400 × 10 = ___; 60 × 50 = ____; 30 × 20 = 600; 700 × 4 = _,_00; 10 × 45 = ____
Answer

All six answers, with the easy way to get each one.

QuestionBreak it upAnswer
100 × 901 × 9 × 100 × 10 = 9 × 1,0009,000
400 × 104 × 100 × 10 = 4 × 1,0004,000
60 × 506 × 5 × 10 × 10 = 30 × 1003,000
30 × 203 × 2 × 10 × 10 = 6 × 100600 (given)
700 × 47 × 4 × 100 = 28 × 1002,800
10 × 4545 tens450
Q3How should we write 450 in the table below?
ProblemThHTO
10 × 45 =    
30 × 20 = 600
400 × 10 =    
700 × 8 =    
100 × 90 =9000
The place value table printed on page 73. Two rows are already filled in.
Answer

Write 4 in the hundreds column, 5 in the tens column and 0 in the ones column. The thousands column stays empty.

NumberThHTO
450450
Q4Fill in the table. Describe the pattern.
ProblemThHTO
10 × 45 =    
30 × 20 = 600
400 × 10 =    
700 × 8 =    
100 × 90 =9000
The place value table printed on page 73. Two rows are already filled in.
Answer

The completed table.

ProblemThHTOAnswer
10 × 45450450
30 × 20600600 (given)
400 × 1040004,000
700 × 856005,600
100 × 9090009,000 (given)
700 × 8
Step 1. 7 × 8 = 56
Step 2. 700 has two zeros, so put two zeros back.
Step 3. Answer = 5,600

The pattern: count the zeros in the two numbers you are multiplying, do the small multiplication first, then write that many zeros after it.

Q5Fill in the tables. Describe the pattern. Discuss in class.
ProblemThHTO
60 × 50 =    
220 × 20 =    
11 × 300 =    
ProblemThHTO
80 × 90 =    
10 × 63 =    
40 × 12 =    
The two place value tables printed on page 73.
Answer

Both tables, completed.

ProblemThHTOAnswer
60 × 5030003,000
220 × 2044004,400
11 × 30033003,300
80 × 9072007,200
10 × 63630630
40 × 12480480
Sample answer for the class discussion: Every product ends in zeros. First multiply the numbers without their zeros, then write all those zeros back: 22 × 2 = 44, so 220 × 20 = 4,400. Careful — the small product can bring a zero of its own: 6 × 5 = 30, so 60 × 50 = 3,000 has three zeros.
Q6What will happen if we multiply numbers by 1,000? 2 × 1,000 = ; 5 × 1,000 = ; 10 × 1,000 = ; 20 × 1,000 =
Answer

Every digit shifts three places to the left, and three zeros appear at the end.

2 × 1,000 = 2 thousand = 2,000
5 × 1,000 = 5 thousand = 5,000
10 × 1,000 = 10 thousand = 10,000
20 × 1,000 = 20 thousand = 20,000
Q7Let us fill in the table and observe the patterns.
ProblemTThThHTO
2 × 1,000 = 2000
5 × 1,000 = 5000
10 × 1,000 =10000
20 × 1,000 =20000
3 × 5,000 =     
8 × 3,000 =     
5 × 7,000 =     
The first table printed on page 74. The first four rows are already filled in.
Answer

The completed table.

ProblemTThThHTOAnswer
2 × 1,00020002,000 (given)
5 × 1,00050005,000 (given)
10 × 1,0001000010,000 (given)
20 × 1,0002000020,000 (given)
3 × 5,0001500015,000
8 × 3,0002400024,000
5 × 7,0003500035,000
Q8Fill in the table.
ProblemTThThHTO
20 × 100 =     
40 × 500 =     
60 × 300 =     
600 × 30 =     
80 × 900 =     
70 × 600 =     
5 × 7,000 =     
The second table printed on page 74.
Answer

The completed table.

ProblemTThThHTOAnswer
20 × 10020002,000
40 × 5002000020,000
60 × 3001800018,000
600 × 301800018,000
80 × 9007200072,000
70 × 6004200042,000
5 × 7,0003500035,000

Many Ways to Multiply — Page 74Five children find 18 × 5

Math Talk
Q1What is 18 × 5?
Answer

18 × 5 = 90.

The easiest one to do in your head
Step 1. Half of 18 is 9.
Step 2. Double of 5 is 10.
Step 3. 9 × 10 = 90
Q2Do you think they are all correct? Why do you think so?

The five children’s ways of finding 18 × 5:

  • Half of 18 is 9. 9 × 5 is 45 and 9 × 5 is 45. I added 45 and 45 together to get 90.
  • First, I doubled 18 to get 36. Then I doubled 36 to get 72 and then I added 18 to 72 to get 90.
  • I separated 18 into 8 and 10. 8 × 5 is 40. 10 × 5 is 50. Then I added 40 and 50 together to get 90.
  • 18 × 5 = 9 × 10. So, 90.
  • I did 20 × 5, which is 100. Then I took away 2 × 5, which is 10. So, 100 − 10 = 90.
Answer

Yes, all five are correct. Every one of them ends at 90, and each one is built on a rule we can trust.

Reason: Each child only broke 18 × 5 into easier parts (halves, doubles, 10 + 8, or 20 − 2) and then put the parts back together. Nothing extra was added and nothing was lost, so all of them get 90.

Doubling and Halving — Pages 75–76Cutting a block of butter packets in half

Doubling and Halving
Q1Butter packets are arranged in the following ways. (a) 3 × 18: Double one, halve the other, to get 6 × 9 = 54. Discuss why these are the same.
3 deep, 18 long → 3 × 18 cut here stacked: 6 deep, 9 long → 6 × 9 Both hold 54 packets.
Cut the block in half and stack it. The shape changes; the number of packets does not.
Answer

They are the same because no packet is added and none is taken away — the block is only cut and re-stacked. 3 × 18 = 6 × 9 = 54.

3 × 18 = 54
Double 3 → 6, halve 18 → 9
6 × 9 = 54 ✓
Q2(b) 22 × 5: fill in ___ × ___ = ____
✂22 × 5___ × ___ = _____
The 22 × 5 block printed on page 75: cut across the middle and put the two halves side by side.
Answer

11 × 10 = 110.

22 × 5
Step 1. Half of 22 = 11
Step 2. Double of 5 = 10
Step 3. 11 × 10 = 110 packets
Q3(c) Solve the following problems like the previous ones (fill in the Half and Double boxes): 14 × 3 = , 38 × 5 = , 16 × 4 = , 35 × 14 =
Answer

Halve the first number, double the second, then multiply.

ProblemHalfDoubleNew problemAnswer
14 × 3767 × 642
38 × 5191019 × 10190
16 × 4888 × 864
35 × 147 (half of 14)70 (double of 35)70 × 7490
Q4This halving and doubling strategy works well when we have to multiply with numbers like 5 and 25. Discuss why?
Answer

Because doubling 5 gives 10, and doubling 25 twice gives 100 — and multiplying by 10 or 100 is the easiest job in arithmetic.

Example with 5
18 × 5 → 9 × 10 = 90

Example with 25
16 × 25 → 8 × 50 = 4 × 100 = 400
Q5(d) Find the product by halving and doubling either the multiplier or the multiplicand. 1) 5 × 18 2) 50 × 28 3) 15 × 22 4) 25 × 12 5) 12 × 45 6) 16 × 45
Answer

All six, each shown as a single easy step.

ProblemHalveDoubleBecomesAnswer
1) 5 × 1818 → 95 → 1010 × 990
2) 50 × 2828 → 1450 → 100100 × 141,400
3) 15 × 2222 → 1115 → 3030 × 11330
4) 25 × 1212 → 625 → 5050 × 6300
5) 12 × 4512 → 645 → 906 × 90540
6) 16 × 4516 → 845 → 908 × 90720
Q6(e) Give 5 examples of multiplication problems where halving and doubling will help in finding the product easily. Find the products as well.
Answer

Pick problems where one number is even and the other is 5, 25 or 50 — those are the ones that climb to 10 or 100.

My exampleHalve and doubleBecomesProduct
5 × 2424 → 12, 5 → 1010 × 12120
25 × 1616 → 8, 25 → 50; again 8 → 4, 50 → 100100 × 4400
15 × 1414 → 7, 15 → 3030 × 7210
5 × 3636 → 18, 5 → 1010 × 18180
50 × 1818 → 9, 50 → 100100 × 9900

Nearest Multiple — Page 76Jump to a friendly number, then adjust

Nearest Multiple
Q1(a) 4 × 19. Observe the picture and find why we need to subtract 4.
The picture for 4 × 19 printed on page 76. Each small square is one item.
Answer

Because the picture shows 4 rows of 20 with one column rubbed out, and that column holds 4 packets.

4 × 19
Step 1. Go to the nearest easy number: 4 × 20 = 80
Step 2. That is one column of 4 too many.
Step 3. 80 − 4 = 76
Q2(b) 14 × 21. Observe the picture and find why we need to add 14.
Figure
The picture for 14 × 21 printed on page 76. Each small square is one item.
Answer

Because 21 columns is 20 columns plus one extra, and that extra column holds 14 packets.

14 × 21
Step 1. 14 × 20 = 280
Step 2. One extra column = 14
Step 3. 280 + 14 = 294
Q3(c) Give 5 examples of problems where you can use the nearest multiple to find the product easily. Find the products as well.
Answer

choose problems where one number is just below or just above a ten, a hundred or a nice multiple.

My exampleNearest multipleAdjustProduct
9 × 3210 × 32 = 320− 32288
99 × 7100 × 7 = 700− 7693
21 × 1520 × 15 = 300+ 15315
49 × 650 × 6 = 300− 6294
101 × 8100 × 8 = 800+ 8808
Q4(d) Find the products of the following numbers by finding the nearest multiple. 1) 7 × 52 2) 12 × 28 3) 75 × 31 4) 99 × 15 5) 8 × 25 6) 22 × 42
Answer

All six, with the friendly number named each time.

ProblemNearest multipleAdjustmentAnswer
1) 7 × 527 × 50 = 350+ 7 × 2 = 14364
2) 12 × 2812 × 30 = 360− 12 × 2 = 24336
3) 75 × 3175 × 30 = 2,250+ 752,325
4) 99 × 15100 × 15 = 1,500− 151,485
5) 8 × 2510 × 25 = 250− 2 × 25 = 50200
6) 22 × 4222 × 40 = 880+ 22 × 2 = 44924

Let Us Solve — Page 77Word problems: use the strategies flexibly

Let Us Solve
Q1A school has an auditorium with 35 rows, with 42 seats in each row. How many people can sit in this auditorium?
Answer

1,470 people can sit in the auditorium.

Total seats = 35 × 42
Step 1. Split 42 into 40 and 2.
Step 2. 35 × 40 = 35 × 4 × 10 = 140 × 10 = 1,400
Step 3. 35 × 2 = 70
Step 4. 1,400 + 70 = 1,470 seats
Q2Priya jogs 4 kilometres every day. How many kilometers will she jog in 31 days?
Answer

Priya will jog 124 kilometres in 31 days.

Total distance = 4 × 31
Step 1. Go to the nearest easy number: 4 × 30 = 120
Step 2. One more day means 4 more kilometres.
Step 3. 120 + 4 = 124 kilometres
Q3A school has received 36 boxes of books with 48 books in each box. How many total books did the school receive in the boxes?
Answer

The school received 1,728 books.

Total books = 36 × 48
Step 1. Split 48 into 40 and 8.
Step 2. 36 × 40 = 36 × 4 × 10 = 144 × 10 = 1,440
Step 3. 36 × 8 = 288
Step 4. 1,440 + 288 = 1,728 books
Q4Priya uses 16 metres of cloth to make 4 kurtas. How much cloth would she need to make 8 kurtas?
Answer

She would need 32 metres of cloth.

Step 1. 8 kurtas = 2 × 4 kurtas
Step 2. Cloth needed = 2 × 16 m
Step 3. 2 × 16 = 32 metres
Q5Gollappa has 29 cows on his farm. Each cow produces 5 litres of milk per day. How many litres of milk do the cow produce in total, each day?
Answer

The cows produce 145 litres of milk each day.

Total milk = 29 × 5
Step 1. Go to the nearest ten: 30 × 5 = 150
Step 2. That counts one cow too many, so take away 5 litres.
Step 3. 150 − 5 = 145 litres
Q6Maska Cow Farm has 297 cows. Each cow requires 18 kg of fodder per day. How much total fodder is needed to feed 297 cows every day?
Answer

5,346 kg of fodder is needed every day.

Total fodder = 297 × 18
Step 1. 297 is close to 300, so start there.
Step 2. 300 × 18 = 3 × 18 × 100 = 54 × 100 = 5,400
Step 3. We counted 3 cows too many. 3 × 18 = 54
Step 4. 5,400 − 54 = 5,346 kg

Waste and Composting — Pages 77–78Nida’s, Kanti’s and John’s ways of multiplying

Waste and Composting
Q1A family of 4 produces around 35 kg of kitchen waste in a month. How much waste will the family produce in a year? The family produces _____ kg of waste in a year.
Answer

The family produces 420 kg of kitchen waste in a year.

Waste in a year = 12 × 35
Step 1. Split 35 into 30 and 5, and 12 into 10 and 2.
Step 2. 10 × 30 = 300
Step 3. 10 × 5 = 50
Step 4. 2 × 30 = 60
Step 5. 2 × 5 = 10
Step 6. 300 + 50 + 60 + 10 = 420 kg
Q2Kanti and John tried to solve it in the following ways. How are these solutions same or different? Discuss in class.
Kanti’s solution
35 (30 + 5)
× 12 (10 + 2)
10 (2 × 5)
60 (2 × 30)
50 (10 × 5)
300 (10 × 30)
420
John’s solution
35 (30 + 5)
× 12 (10 + 2)
60 + 10 = 70 (2 × 35)
300 + 50 = 350 (10 × 35)
= 420
Answer

Both are the same idea; they only differ in how many lines they write. Both split 35 into 30 + 5 and 12 into 10 + 2, and both reach 420.

Kanti writes four linesJohn writes two lines
10 (2 × 5)60 + 10 = 70 (2 × 35)
60 (2 × 30)
50 (10 × 5)300 + 50 = 350 (10 × 35)
300 (10 × 30)
Total 420Total 420
Q3The family regularly composts the collected waste. They get around 150 kg of compost each year, which they use in their garden. 1 kg of compost is often sold in the market at ₹24. By creating their own compost, how much money have they saved in a year?
Answer

The family saves ₹3,600 in a year.

Money saved = 24 × 150
Step 1. Split 150 into 100 + 50, and 24 into 20 + 4.
Step 2. 20 × 100 = 2,000
Step 3. 20 × 50 = 1,000
Step 4. 4 × 100 = 400
Step 5. 4 × 50 = 200
Step 6. 2,000 + 1,000 + 400 + 200 = ₹3,600

Let Us Multiply — Page 79Filling the grid and the column methods

Let Us Multiply
Q1(a) 32 × 8. Fill the grid and complete the two column methods.
×302
8  
  
32 (30 + 2)×8____ (8 × 2)__0 (8 × 30)256
32 (30 + 2)× 8____0 + 16 = 256
The grid and the two column methods printed on page 79. Some numbers are already filled in.
Answer

32 × 8 = 256. Here is every blank filled in.

×302
824016
Total240 + 16 = 256
Column method, all the pieces
32 (30 + 2)
× 8
Step 1. 8 × 2 = 16
Step 2. 8 × 30 = 240
Step 3. 16 + 240 = 256
Column method, joined up
32 (30 + 2)
× 8
240 + 16 = 256
Q2(b) 69 × 45. Fill the grid and complete the column methods.
×609
40  
5  
 2700405
 3105
69 (60 + 9)× 45 (40 + 5)45 (5 × 9)___0 (5 × 60)___0 (40 × 9)__00 (40 × 60)3,105
69 (60 + 9)× 45 (40 + 5)300 + __ = 345 (5 × 69)____ + ___ = 2760 (40 × 69)= 3,105
The grid and the two column methods printed on page 79. Some numbers are already filled in.
Answer

69 × 45 = 3,105. Every blank filled in.

×609Row total
402,4003602,760
530045345
Column total2,7004053,105
Column method, all four pieces
69 (60 + 9) × 45 (40 + 5)
Step 1. 5 × 9 = 45
Step 2. 5 × 60 = 300
Step 3. 40 × 9 = 360
Step 4. 40 × 60 = 2,400
Step 5. 45 + 300 + 360 + 2,400 = 3,105
Column method, two rows
Step 1. 300 + 45 = 345 (5 × 69)
Step 2. 2,400 + 360 = 2,760 (40 × 69)
Step 3. 345 + 2,760 = 3,105

Let Us Do — Pages 79–80Solve like Nida, like Kanti, like John; then word problems

Let Us Do
Q1Solve the following problems like Nida did (using a grid). a) 78 × 4 b) 83 × 9 c) 67 × 28 d) 53 × 37

Nida’s solution (12 × 35 kg, from the kitchen-waste problem):

×30 kg5 kg
1030050
26010
36060
420

a) 78 × 4

×  
   
  

b) 83 × 9

×  
   
  

c) 67 × 28

×  
   
   
   
  

d) 53 × 37

×  
   
   
   
  
Answer

Nida’s way is to draw a grid, split each number into its place values, multiply every box, then add.

a) 78 × 4 = 312

×708
428032
Total280 + 32 = 312

b) 83 × 9 = 747

×803
972027
Total720 + 27 = 747

c) 67 × 28 = 1,876

×607Row total
201,2001401,340
848056536
Total1,340 + 536 = 1,876

d) 53 × 37 = 1,961

×503Row total
301,500901,590
735021371
Total1,590 + 371 = 1,961
Q2Solve the following problems like Kanti. a) 94 × 5 b) 49 × 6 c) 37 × 53 d) 28 × 79
Answer

Kanti’s way is to write every small piece on its own line, smallest first, then add them all.

a) 94 × 5
94 (90 + 4) × 5
Step 1. 5 × 4 = 20
Step 2. 5 × 90 = 450
Step 3. 20 + 450 = 470
b) 49 × 6
49 (40 + 9) × 6
Step 1. 6 × 9 = 54
Step 2. 6 × 40 = 240
Step 3. 54 + 240 = 294
c) 37 × 53
37 (30 + 7) × 53 (50 + 3)
Step 1. 3 × 7 = 21
Step 2. 3 × 30 = 90
Step 3. 50 × 7 = 350
Step 4. 50 × 30 = 1,500
Step 5. 21 + 90 + 350 + 1,500 = 1,961
d) 28 × 79
28 (20 + 8) × 79 (70 + 9)
Step 1. 9 × 8 = 72
Step 2. 9 × 20 = 180
Step 3. 70 × 8 = 560
Step 4. 70 × 20 = 1,400
Step 5. 72 + 180 + 560 + 1,400 = 2,212
Q3Solve the following problems like John. a) 86 × 3 b) 72 × 7 c) 94 × 36 d) 66 × 22
Answer

John’s way is one line for each digit of the second number, with the pieces of that line already added together.

a) 86 × 3
Step 1. 3 × 86 → 240 + 18 = 258
b) 72 × 7
Step 1. 7 × 72 → 490 + 14 = 504
c) 94 × 36
Step 1. 6 × 94 → 540 + 24 = 564
Step 2. 30 × 94 → 2,700 + 120 = 2,820
Step 3. 564 + 2,820 = 3,384
d) 66 × 22
Step 1. 2 × 66 → 120 + 12 = 132
Step 2. 20 × 66 → 1,200 + 120 = 1,320
Step 3. 132 + 1,320 = 1,452
Q4(a) A movie theater has 8 rows of seats, and each row has 12 seats. If half the seats are filled, how many people are watching the movie? If 3 more rows get filled, how many total people will be there?
Answer

48 people are watching. After 3 more rows fill up, there will be 84 people.

Step 1. Total seats = 8 × 12 = 96 seats
Step 2. Half the seats = 96 ÷ 2 = 48 people
Step 3. Seats in 3 more rows = 3 × 12 = 36 seats
Step 4. New total = 48 + 36 = 84 people
Q5(b) In a test match between India and West Indies, the Indian team hit twenty-four 4s and eighteen 6s across the two innings. How many runs were scored in 4s and 6s each? 234 runs were made by running between the wickets. If 23 runs were extras, how many runs were scored by Indian team in the two innings?
Answer

Runs in 4s = 96. Runs in 6s = 108. Total runs in the two innings = 461.

Runs from fours
Step 1. 24 fours = 24 × 4
Step 2. 24 × 4 = 96 runs
Runs from sixes
Step 1. 18 sixes = 18 × 6
Step 2. 18 × 6 = 108 runs
Total for the team
Step 1. Boundaries = 96 + 108 = 204 runs
Step 2. Add the running between wickets: 204 + 234 = 438 runs
Step 3. Add the extras: 438 + 23 = 461 runs
Q6(c) Anjali buys 15 bulbs and 12 tube lights from Sudha Electricals. Each bulb costs ₹25 and each tube light costs ₹34. How much money should Anjali give to the shopkeeper?
Answer

Anjali should give ₹783 to the shopkeeper.

Cost of bulbs
Step 1. 15 bulbs × ₹25 each
Step 2. 15 × 25 = 10 × 25 + 5 × 25 = 250 + 125 = ₹375
Cost of tube lights
Step 1. 12 tube lights × ₹34 each
Step 2. 12 × 34 = 10 × 34 + 2 × 34
Step 3. 340 + 68 = ₹408
Total to pay
₹375 + ₹408 = ₹783
Q7(d) A shopkeeper sold 28 bags of rice. Each bag costs ₹350. How much money did he earn by selling rice bags?
Answer

He earned ₹9,800.

Money earned = 28 × 350
Step 1. Set the zero of 350 aside: 28 × 35
Step 2. 28 × 35 = 28 × 30 + 28 × 5
Step 3. 28 × 30 = 840
Step 4. 28 × 5 = 140
Step 5. 840 + 140 = 980
Step 6. Put the zero back: ₹9,800
Q8(e) A school library has 86 shelves and each shelf has 162 books. Find the number of books in the library.
Answer

The library has 13,932 books.

Total books = 86 × 162
Step 1. Split 162 into 100 + 60 + 2.
Step 2. 86 × 100 = 8,600
Step 3. 86 × 60 = 5,160
Step 4. 86 × 2 = 172
Step 5. 8,600 + 5,160 + 172 = 13,932 books

Dairy Cooperative — Pages 81–83Mili’s father’s method: multiplying with place values

Dairy CooperativeMath Talk
Q1A dairy cooperative in a small town gets its milk from 268 villagers. Each villager has at least 4 milk-giving cows. What is the minimum number of cows the dairy cooperative gets its milk from?
Answer

The dairy cooperative gets milk from at least 1,072 cows.

Minimum cows = 268 × 4
Step 1. Split 268 into 200 + 60 + 8.
Step 2. 4 × 200 = 800
Step 3. 4 × 60 = 240
Step 4. 4 × 8 = 32
Step 5. 800 + 240 + 32 = 1,072 cows
Q2Discuss how this multiplication is being carried out! (Mili’s father’s method for 268 × 4, with 30 added to 4 × 60 and 200 added to 4 × 200)
ThHTO 2 3 268 ×4 1072 The circled digits are the carries: 3 tens and 2 hundreds.
The carried 3 joins 4 × 60, not 60. The carried 2 joins 4 × 200, not 200.
Answer

In Mili’s father’s method you multiply one column at a time, from the right, and any extra tens or hundreds are carried to the next column — where they are added to the product, not to the original digit.

268 × 4
Ones: 4 × 8 = 32 → write 2, carry 3 tens
Tens: 4 × 6 tens = 24 tens; 24 + 3 = 27 tens → write 7, carry 2 hundreds
Hundreds: 4 × 2 hundreds = 8 hundreds; 8 + 2 = 10 hundreds → write 0, and 1 in thousands
Answer: 1,072
Q3The villagers rear various breeds of cows. Among the villagers, there are 453 Gir cows. Each of these cows give 13 litres of milk each day. How many litres of milk does the dairy cooperative receive from Gir cows everyday?
Answer

The cooperative receives 5,889 litres of milk from Gir cows every day.

Milk each day = 453 × 13
Step 1. Multiply by the 3 first.
3 × 400 = 1,200
3 × 50 = 150
3 × 3 = 9
Step 2. Add them: 1,200 + 150 + 9 = 1,359

Step 3. Now multiply by the 10.
10 × 400 = 4,000
10 × 50 = 500
10 × 3 = 30
Step 4. Add them: 4,000 + 500 + 30 = 4,530

Step 5. 1,359 + 4,530 = 5,889 litres
Q4The dairy cooperative sells 1 kg cow ghee for ₹574. The cooperative is able to produce around 125 kg of ghee in a month. How much do they earn by selling ghee in a month?
Answer

The cooperative earns ₹71,750 in a month.

Earnings = 574 × 125

Row 1 — multiply by 5
5 × 500 = 2,500
5 × 70 = 350
5 × 4 = 20
2,500 + 350 + 20 = 2,870

Row 2 — multiply by 20
20 × 500 = 10,000
20 × 70 = 1,400
20 × 4 = 80
10,000 + 1,400 + 80 = 11,480

Row 3 — multiply by 100
100 × 500 = 50,000
100 × 70 = 7,000
100 × 4 = 400
50,000 + 7,000 + 400 = 57,400

Add the three rows
2,870 + 11,480 + 57,400 = ₹71,750
Q5Discuss what the same coloured digits might mean. (Working for 574 × 125 printed on page 83.)
574 (500 + 70 + 4)
× 125 (100 + 20 + 5)
2,500 + 350 + 20 = 2,870 (5 × 574)
10,000 + 1,400 + 80 = 11,480 (20 × 574)
50,000 + 7,000 + 400 = 57,400 (100 × 574)
= 71,750
TThThHTO132574×125287011480+5740071750
The book’s working for 574 × 125. Same-coloured digits in the rows, and the circled carries in the column method.
Answer

Digits of the same colour stand in the same place value, so they are added together to make one digit of that row’s answer. The 2 of 20, the 3 of 350 and the 1 of 1,400 are the carries of the column method.

5 × 574: blue 5 (of 2,500) + blue 3 (of 350) = 8 hundreds; red 5 (of 350) + red 2 (of 20) = 7 tens → 2,870
20 × 574: orange 10 (of 10,000) + orange 1 (of 1,400) = 11 thousands → 11,480

Let Us Solve — Pages 83–84Practise Nida’s, John’s and Mili’s father’s methods

Let Us Solve
Q1Solve the following problems like Nida. a) 548 × 6 b) 682 × 3 c) 324 × 18 d) 507 × 23 e) 190 × 65
Answer

Nida’s grid: split both numbers into place values, multiply every box, add everything.

a) 548 × 6 = 3,288

×500408
63,00024048
3,000 + 240 + 48 = 3,288

b) 682 × 3 = 2,046

×600802
31,8002406
1,800 + 240 + 6 = 2,046

c) 324 × 18 = 5,832

×300204Row total
103,000200403,240
82,400160322,592
3,240 + 2,592 = 5,832

d) 507 × 23 = 11,661

×50007Row total
2010,000014010,140
31,5000211,521
10,140 + 1,521 = 11,661

e) 190 × 65 = 12,350

×10090Row total
606,0005,40011,400
5500450950
11,400 + 950 = 12,350
Q2Solve the following problems like John. a) 123 × 84 b) 368 × 32 c) 159 × 324 d) 239 × 401 e) 592 × 5 f) 101 × 22
Answer

John’s way: one line for each digit of the multiplier, with that line’s pieces already added.

a) 123 × 84 = 10,332
Step 1. 4 × 123 → 400 + 80 + 12 = 492
Step 2. 80 × 123 → 8,000 + 1,600 + 240 = 9,840
Step 3. 492 + 9,840 = 10,332
b) 368 × 32 = 11,776
Step 1. 2 × 368 → 600 + 120 + 16 = 736
Step 2. 30 × 368 → 9,000 + 1,800 + 240 = 11,040
Step 3. 736 + 11,040 = 11,776
c) 159 × 324 = 51,516
Step 1. 4 × 159 → 400 + 200 + 36 = 636
Step 2. 20 × 159 → 2,000 + 1,000 + 180 = 3,180
Step 3. 300 × 159 → 30,000 + 15,000 + 2,700 = 47,700
Step 4. 636 + 3,180 + 47,700 = 51,516
d) 239 × 401 = 95,839
Step 1. 1 × 239 = 239
Step 2. 0 × 239 = 0
Step 3. 400 × 239 → 80,000 + 12,000 + 3,600 = 95,600
Step 4. 239 + 0 + 95,600 = 95,839
e) 592 × 5 = 2,960
Step 1. 5 × 592 → 2,500 + 450 + 10 = 2,960
f) 101 × 22 = 2,222
Step 1. 2 × 101 → 200 + 0 + 2 = 202
Step 2. 20 × 101 → 2,000 + 0 + 20 = 2,020
Step 3. 202 + 2,020 = 2,222
Q3Let us solve a few questions like Mili’s father. Fill the boxes and the circles (carries).
ThHTO806×9
TThThHTO3455×26+
TThThHTO143×20832+00
The three Mili’s-father templates on page 84 (806 × 9, 455 × 26, 143 × 208), redrawn. The given digits are printed; the small red 3 and 2 in the third one are carries the book writes in. A total row is added to the second and third.
Answer

806 × 9 = 7,254; 455 × 26 = 11,830; 143 × 208 = 29,744. Here is every box filled.

ThHTO5806×97254
TThThHTO1133455×262730+910011830
TThThHTO32143×2081144320000+2860029744
Filled in. Purple circles: carries while multiplying by the ones digit; green circles: carries while multiplying by the tens digit.
Q4Now use Mili’s father’s method to solve the following questions. (a) 807 × 5 (b) 143 × 28 (c) 309 × 9
Answer
(a) 807 × 5 = 4,035
Step 1. 5 × 7 = 35 → write 5, carry 3
Step 2. 5 × 0 tens = 0, add carry 3 → write 3
Step 3. 5 × 8 hundreds = 40 hundreds → write 0 in hundreds, 4 in thousands
Answer: 4,035
(b) 143 × 28 = 4,004
Row 1 — the 8
8 × 3 = 24 → write 4, carry 2
8 × 4 tens = 32 tens + 2 tens = 34 tens → write 4, carry 3
8 × 1 hundred = 8 hundreds + 3 hundreds = 11 hundreds
Row 1 = 1,144

Row 2 — the 2 tens
20 × 143 = 2,860

Total = 1,144 + 2,860 = 4,004
(c) 309 × 9 = 2,781
Step 1. 9 × 9 = 81 → write 1, carry 8
Step 2. 9 × 0 tens = 0, add carry 8 → write 8
Step 3. 9 × 3 hundreds = 27 hundreds → write 7 in hundreds, 2 in thousands
Answer: 2,781
Q5(d) 450 × 38 (e) 584 × 23 (f) 302 × 13
Answer
(d) 450 × 38 = 17,100
Row 1 — the 8: 8 × 450 = 3,600
Row 2 — the 3 tens: 30 × 450 = 13,500
Total = 3,600 + 13,500 = 17,100
(e) 584 × 23 = 13,432
Row 1 — the 3
3 × 4 = 12 → write 2, carry 1
3 × 8 tens = 24 tens + 1 ten = 25 tens → write 5, carry 2
3 × 5 hundreds = 15 hundreds + 2 hundreds = 17 hundreds
Row 1 = 1,752

Row 2 — the 2 tens: 20 × 584 = 11,680

Total = 1,752 + 11,680 = 13,432
(f) 302 × 13 = 3,926
Row 1 — the 3: 3 × 302 = 906
Row 2 — the 1 ten: 10 × 302 = 3,020
Total = 906 + 3,020 = 3,926
Q6(g) 604 × 54 (h) 112 × 23 (i) 237 × 19
Answer
(g) 604 × 54 = 32,616
Row 1 — the 4: 4 × 604 = 2,416
Row 2 — the 5 tens: 50 × 604 = 30,200
Total = 2,416 + 30,200 = 32,616
(h) 112 × 23 = 2,576
Row 1 — the 3: 3 × 112 = 336
Row 2 — the 2 tens: 20 × 112 = 2,240
Total = 336 + 2,240 = 2,576
(i) 237 × 19 = 4,503
Row 1 — the 9
9 × 7 = 63 → write 3, carry 6
9 × 3 tens = 27 tens + 6 tens = 33 tens → write 3, carry 3
9 × 2 hundreds = 18 hundreds + 3 hundreds = 21 hundreds
Row 1 = 2,133

Row 2 — the 1 ten: 10 × 237 = 2,370

Total = 2,133 + 2,370 = 4,503

Check, Check! — Page 85Are these children’s solutions correct?

Check, Check!
Q1Check if the child’s solution is correct. If correct, explain why the solution is correct. If it is incorrect, identify the error and correct the solution.
(a) Asma’s solution for 46 × 59
46
× 59
2,000
300
360
54
2,714
Answer

Asma is correct. 46 × 59 = 2,714.

Her lineWhere it comes fromCheck
2,00050 × 402,000 ✓
30050 × 6300 ✓
3609 × 40360 ✓
549 × 654 ✓
2,000 + 300 = 2,300
2,300 + 360 = 2,660
2,660 + 54 = 2,714 ✓
Q2Check if the child’s solution is correct. If correct, explain why the solution is correct. If it is incorrect, identify the error and correct the solution.
(b) Pankaj’s solution for 203 × 54
203
× 54
80 + 12 = 92
100 + 15 = 115
= 135
Answer

Pankaj is wrong. The correct answer is 203 × 54 = 10,962. He made three mistakes.

  1. He treated 203 as 20 + 3. His rows are 4 × 20 + 4 × 3 = 92 and 5 × 20 + 5 × 3 = 115, which is 4 × 23 and 5 × 23. The 2 in 203 is 2 hundreds = 200.
  2. He used 5 instead of 50. The 5 in 54 is 5 tens, so the second row must be 50 × 203.
  3. His addition is wrong too: 92 + 115 = 207, not 135.
Correct solution: 203 (200 + 0 + 3) × 54 (50 + 4)
4 × 203 = 800 + 0 + 12 = 812
50 × 203 = 10,000 + 0 + 150 = 10,150
812 + 10,150 = 10,962
Q3Check if the child’s solution is correct. If correct, explain why the solution is correct. If it is incorrect, identify the error and correct the solution.
(c) Lado’s solution for 38 × 150
38
× 150
1,500 + 400 = 1,900
3,000 + 800 = 3,800
= 5,700
Answer

Lado is correct. 38 × 150 = 5,700.

Her rowWhere it comes fromRow total
1,500 + 40050 × 30 and 50 × 81,900 (= 50 × 38)
3,000 + 800100 × 30 and 100 × 83,800 (= 100 × 38)
1,900 + 3,800 = 5,700 ✓
Q4Check if the child’s solution is correct. If correct, explain why the solution is correct. If it is incorrect, identify the error and correct the solution.
(d) Kira’s solution for 193 × 272
193
× 272
200 + 180 + 6 = 386
700 + 630 + 21 = 1,351
20,000 + 18,000 + 600 = 38,600
= 40,337
Answer

Kira is wrong. The correct answer is 193 × 272 = 52,496.

The error is in row 2. The 7 in 272 is 7 tens, so the row must be 70 × 193 = 13,510, not 7 × 193 = 1,351. Rows 1 and 3 are correct.

The correct working
Row 1 (the 2): 2 × 193 = 386
Row 2 (the 7 tens): 70 × 193 = 7,000 + 6,300 + 210 = 13,510
Row 3 (the 2 hundreds): 200 × 193 = 38,600

386 + 13,510 = 13,896
13,896 + 38,600 = 52,496
Q5Check if the child’s solution is correct. If correct, explain why the solution is correct. If it is incorrect, identify the error and correct the solution.

(e) Asher’s solution for 626 × 323 (carries 1, 1, 1 in the top row)

ThHTO
111
626
×323
1878
1252
+1878
5018
Answer

Asher is wrong. The correct answer is 626 × 323 = 2,02,198.

The error: the rows are not moved to the left. Row 2 is 2 tens × 626 = 12,520 and row 3 is 3 hundreds × 626 = 1,87,800. (His own addition is also wrong: 1,878 + 1,252 + 1,878 = 5,008, not 5,018.)

The correct working
Row 1 (the 3 ones): 3 × 626 = 1,878
Row 2 (the 2 tens): 20 × 626 = 12,520
Row 3 (the 3 hundreds): 300 × 626 = 1,87,800

1,878 + 12,520 = 14,398
14,398 + 1,87,800 = 2,02,198

Let Us Do — Pages 86–87Same answers without calculating, easy ways, and using a known product

Let Us Do
Q1Identify the problems that have the same answer as the one given at the top of each box. Do not calculate.
Top of the boxProblems in the box
12 × 1711 × 18  ·  6 × 34
26 × 1126 × 10 and 26 × 1  ·  20 × 11 and 6 × 11
18 × 49 × 8  ·  20 × 4 − 8
55 × 950 × 9 and 5 × 9  ·  54 × 10  ·  55 × 10 − 55
101 × 42100 × 42 and 100  ·  100 × 42 and 42
247 × 8250 × 8 − 24  ·  247 × 10 − 247
1001 × 51,000 × 6  ·  1,000 × 5 and 5
1999 × 22,000 × 2 − 4  ·  2,000 × 2 − 2
Answer

Same answer as the top of the box: 6 × 34; 26 × 10 and 26 × 1; 20 × 11 and 6 × 11; 9 × 8; 20 × 4 − 8; 50 × 9 and 5 × 9; 55 × 10 − 55; 100 × 42 and 42; 250 × 8 − 24; 1,000 × 5 and 5; 2,000 × 2 − 2.

BoxOptionSame?Reason
12 × 1711 × 18NoNeither number was halved or doubled; this is a different product
12 × 176 × 34Yes12 halved is 6, 17 doubled is 34
26 × 1126 × 10 and 26 × 1Yes11 = 10 + 1
26 × 1120 × 11 and 6 × 11Yes26 = 20 + 6
18 × 49 × 8Yes18 halved is 9, 4 doubled is 8
18 × 420 × 4 − 8Yes18 is 2 less than 20, and 2 × 4 = 8
55 × 950 × 9 and 5 × 9Yes55 = 50 + 5
55 × 954 × 10NoYou may not change both numbers like that
55 × 955 × 10 − 55Yes9 is one less than 10, so take away one 55
101 × 42100 × 42 and 100NoThe extra piece is one 42, not one 100
101 × 42100 × 42 and 42Yes101 = 100 + 1, so add one 42
247 × 8250 × 8 − 24Yes247 is 3 less than 250, and 3 × 8 = 24
247 × 8247 × 10 − 247NoThat gives 247 × 9, not 247 × 8
1001 × 51,000 × 6NoBoth numbers were changed with nothing to balance it
1001 × 51,000 × 5 and 5Yes1001 = 1000 + 1, so add one 5
1999 × 22,000 × 2 − 4No1999 is only 1 less than 2000, so we must take away one 2, not 4
1999 × 22,000 × 2 − 2Yes1999 = 2000 − 1, so take away one 2
Q2Find easy ways of solving these problems. (a) 16 × 25 (b) 12 × 125 (c) 24 × 250
Answer

All three become easy if you climb to 100, 500 or 1,000 by doubling.

(a) 16 × 25 = 400
Step 1. Halve 16 to 8, double 25 to 50 → 8 × 50
Step 2. Halve 8 to 4, double 50 to 100 → 4 × 100
Step 3. 4 × 100 = 400
(b) 12 × 125 = 1,500
Step 1. Halve 12 to 6, double 125 to 250 → 6 × 250
Step 2. Halve 6 to 3, double 250 to 500 → 3 × 500
Step 3. 3 × 500 = 1,500
(c) 24 × 250 = 6,000
Step 1. Halve 24 to 12, double 250 to 500 → 12 × 500
Step 2. Halve 12 to 6, double 500 to 1,000 → 6 × 1,000
Step 3. 6 × 1,000 = 6,000
Q3(d) 36 × 25 (e) 28 × 75 (f) 300 × 15
Answer
(d) 36 × 25 = 900
Step 1. Halve 36 to 18, double 25 to 50 → 18 × 50
Step 2. Halve 18 to 9, double 50 to 100 → 9 × 100
Step 3. 9 × 100 = 900
(e) 28 × 75 = 2,100
Step 1. Notice 75 is three 25s, and 28 is four 7s.
Step 2. 28 × 75 = 7 × 4 × 75 = 7 × 300
Step 3. 7 × 300 = 2,100
(f) 300 × 15 = 4,500
Step 1. Set the zeros aside: 3 × 15 = 45
Step 2. 300 has two zeros, so put two zeros back.
Step 3. Answer = 4,500
Q4(g) 50 × 78 (h) 199 × 63 (i) 128 × 35
Answer
(g) 50 × 78 = 3,900
Step 1. Double 50 to 100, halve 78 to 39 → 100 × 39
Step 2. 100 × 39 = 3,900
(h) 199 × 63 = 12,537
Step 1. 199 is one less than 200, so use the nearest multiple.
Step 2. 200 × 63 = 12,600
Step 3. That is one group of 63 too many.
Step 4. 12,600 − 63 = 12,537
(i) 128 × 35 = 4,480
Step 1. Halve 128 to 64, double 35 to 70 → 64 × 70
Step 2. 64 × 7 = 448
Step 3. Put back the zero from 70: 4,480
Q5Write 5 other examples for which you can find easy ways of getting products.
Answer

the easiest problems are the ones where a number is close to 10, 100 or 1,000, or where doubling turns it into one of those.

My exampleThe easy wayProduct
32 × 2516 × 50 = 8 × 100800
98 × 45100 × 45 − 2 × 45 = 4,500 − 904,410
64 × 12532 × 250 = 16 × 500 = 8 × 1,0008,000
1,001 × 71,000 × 7 + 77,007
45 × 2090 × 10900
Q6Find the answers to the following questions based on the given information. (a) 17 × 23 = 391 (b) 17 × 24 = ___ (c) 17 × 22 = ___ (d) 16 × 23 = ___
Answer

(b) 408 (c) 374 (d) 368. You do not need to multiply again — just add or take away one whole group.

  1. (b) 17 × 24. This is one more group of 17 than 17 × 23. So 391 + 17 = 408.
  2. (c) 17 × 22. This is one group of 17 fewer. So 391 − 17 = 374.
  3. (d) 16 × 23. Here the other number went down by 1, so we lose one group of 23. So 391 − 23 = 368.
Q7(e) 8 × 9 = 72 (f) 18 × 9 = ___ (g) 28 × 9 = ___ (h) 108 × 9 = ___ (i) 18 × 23 = ___
Answer

(f) 162 (g) 252 (h) 972 (i) 414.

  1. (f) 18 × 9. 18 is 8 + 10, so add ten more 9s. 72 + 90 = 162.
  2. (g) 28 × 9. 28 is 18 + 10, so add ten more 9s again. 162 + 90 = 252. (Or from 8 × 9: 72 + 180 = 252.)
  3. (h) 108 × 9. 108 is 8 + 100, so add a hundred 9s. 72 + 900 = 972.
  4. (i) 18 × 23. Go back to 17 × 23 = 391. One more row of 23 gives 391 + 23 = 414.
Q8To find 17 × 24, how much is to be added to 17 × 23 — 17 or 23?
23172417
The pictures on page 87: 17 × 23 and 17 × 24 (the extra column is blue).
Answer

Add 17. 17 × 24 has one more column than 17 × 23, and each column has 17 squares. So 17 × 24 = 391 + 17 = 408.

Q9To find 18 × 23, how much is to be added to 17 × 23 — 17 or 23?
23172318
The pictures on page 87: 17 × 23 and 18 × 23 (the extra row is blue).
Answer

Add 23. 18 × 23 has one more row than 17 × 23, and each row has 23 squares. So 18 × 23 = 391 + 23 = 414.

Let Us Think — Pages 87–88Coloured box puzzles and estimating products

Let Us Think
Q1Find the possible values of the coloured boxes in each of the following problems. The same colour indicates the same number in a problem. Some problems can have more than one answer.
a)×3
b)×3
c)×3
Puzzles (a)–(c) on page 87. The top boxes have no colour; all the answer boxes are orange.
Answer

(a) 11 × 3 = 33, 22 × 3 = 66, 33 × 3 = 99
(b) 111 × 3 = 333, 222 × 3 = 666, 333 × 3 = 999
(c) 1,111 × 3 = 3,333, 2,222 × 3 = 6,666, 3,333 × 3 = 9,999

Reason: all the answer boxes are orange, so every digit of the product is the same. In (a) the product must be 11, 22, …, 99 and also in the 3 times table: only 33, 66 and 99 are (3 × 11, 3 × 22, 3 × 33). (b) and (c) work the same way. The top boxes have no colour, so they need not match.

Q2d), e), f): find the numbers in the coloured boxes. The same colour indicates the same number in a problem.
d)×510
e)×50
f)×510
Puzzles (d)–(f) on page 88.
Answer

(d) any even two-digit number from 20 to 38. (e) 110 × 5 = 550, the only answer. (f) 2,222 × 5 = 11,110 or 3,332 × 5 = 16,660.

Q3g), h), i): find the numbers in the coloured boxes. The same colour indicates the same number in a problem.
g)×9
h)×5,999
i)×2,000
Puzzles (g)–(i) on page 88. In (h) the multiplier box is purple like the last top box; in (i) it is green like the middle top box.
Answer

(g) 202 × 9 = 1,818, 303 × 9 = 2,727, … up to 909 × 9 = 8,181 (eight answers). (h) 857 × 7 = 5,999. (i) no answer — see About the book.

Q4Estimate the products on the left and match them to the numbers given on the right. (25 × 31, 132 × 19, 101 × 11, 248 × 49, 12 × 25) with (2,600; 12,500; 300; 750; 1,000). Discuss how you estimated.
Answer

Round each number to a friendly one, then multiply.

ProblemRound it toEstimateMatchesExact answer
25 × 3125 × 30750750775
132 × 19130 × 202,6002,6002,508
101 × 11100 × 101,0001,0001,111
248 × 49250 × 5012,50012,50012,152
12 × 2512 × 25300300300

The King’s Reward — Pages 88–89Three ministers, three choices of gold

The King’s Reward
Q1Which of the rewards would you have chosen?

Choice 1: Take 5 gold coins and double the number of coins every day for 7 days.
Choice 2: Take 3 gold coins and triple the number of coins every day for 7 days.
Choice 3: Take 1 gold coin and multiply the number of coins by 5 every day for 7 days.

Answer

Sample answer: I would choose Choice 3 — take 1 gold coin and multiply the number of coins by 5 every day for 7 days. It ends with by far the most gold.

A quick look at day 3
Choice 1: 5 → 10 → 20 → 40
Choice 2: 3 → 9 → 27 → 81
Choice 3: 1 → 5 → 25 → 125
Already the smallest start is winning.
Q2After a week, the 3 ministers were surprised at the final amount of gold coins. Guess who received the most gold coins? Calculate how much gold coins each minister received.
Answer

Minister 3 received the most: 78,125 gold coins. Minister 1 got 640 and Minister 2 got 6,561.

DayMinister 1 (start 5, double)Minister 2 (start 3, triple)Minister 3 (start 1, × 5)
Start531
11095
2202725
34081125
480243625
51607293,125
63202,18715,625
76406,56178,125

Multiplication Patterns — Pages 89–90How the product changes, and number-pair grids

Multiplication Patterns
Q1Notice how the multiplier, multiplicand, and products are changing. What is the relationship of the new product with the original product? a) 16 × 44 = 704; 1) 8 × 88 = 704; 2) 8 × 22 = 176; 3) 16 × 22 = ___; 4) 32 × 44 = ___
Answer

3) 16 × 22 = 352 and 4) 32 × 44 = 1,408.

ProblemWhat changedEffect on the productAnswer
16 × 44 = 704the original—704
1) 8 × 8816 halved, 44 doubledno change704
2) 8 × 22both halvedone quarter of 704176
3) 16 × 2244 halved onlyhalf of 704352
4) 32 × 4416 doubled onlydouble of 7041,408
Q2b) 12 × 32 = 384; 1) 6 × 16 = ___; 2) 24 × 16 = ___; 3) 24 × 64 = ___; 4) 12 × 16 = ___
Answer

1) 96 2) 384 3) 1,536 4) 192

ProblemWhat changedEffect on 384Answer
12 × 32 = 384the original—384
1) 6 × 16both halvedone quarter96
2) 24 × 1612 doubled, 32 halvedno change384
3) 24 × 64both doubledfour times1,536
4) 12 × 1632 halved onlyhalf192
Q3Observe and complete the given pattern: 1 × 1 = 1; 11 × 11 = 121; 111 × 111 = 12,321; 1111 × 1111 = ___
Answer

1111 × 1111 = 12,34,321.

1 × 1 = 1
11 × 11 = 121
111 × 111 = 12,321
1111 × 1111 = 12,34,321
(and 11111 × 11111 = 12,34,54,321)
Q4Observe and complete: 11 × 12 = 132; 11 × 34 = 374; 11 × 56 = 616; 11 × 78 = 858; 11 × 54 = ___; 11 × 82 = ___
Answer

11 × 54 = 594 and 11 × 82 = 902.

  1. 11 × 54. Split 54 into 5 and 4. Write 5, then 5 + 4 = 9, then 4. That gives 594.
  2. 11 × 82. Split 82 into 8 and 2. Write 8, then 8 + 2 = 10 — this is more than 9, so keep the 0 and carry the 1 to the 8, making 9. Then write 2. That gives 902.
Q5Observe and complete: 5 × 5 = 25; 15 × 15 = 225; 25 × 25 = 625; 35 × 35 = 1,225; 45 × 45 = ___; 55 × 55 = ___
Answer

45 × 45 = 2,025 and 55 × 55 = 3,025.

ProblemFront partEndAnswer
25 × 252 × 3 = 625625
35 × 353 × 4 = 12251,225
45 × 454 × 5 = 20252,025
55 × 555 × 6 = 30253,025
Q6Observe and complete: 1 × 9 + 1 = 10; 12 × 9 + 2 = 110; 123 × 9 + 3 = 1,110; 1,234 × 9 + 4 = ___
Answer

1,234 × 9 + 4 = 11,110.

  1. Multiply first. 1,234 × 9. Use the nearest multiple: 1,234 × 10 = 12,340, then take away one 1,234.
  2. 12,340 − 1,234 = 11,106.
  3. Now add 4. 11,106 + 4 = 11,110.
Q7Here are some numbers. Any two adjacent numbers in a row or a column are number pairs. Can you identify the pair whose product is the smallest and another pair whose product is the largest? Do you need to find every product or can you find this by looking at the numbers?
83575
326213
661114
The number grid on page 90. Neighbours in a row or a column are joined.
Answer

Smallest product: 11 × 14 = 154. Largest product: 35 × 75 = 2,625. No, you do not need to work out every product — you can see it by looking.

Reason: the smallest product comes from the two smallest numbers that are neighbours (11 and 14); the largest from the two largest neighbours (35 and 75).

Let Us Solve — Page 91The last set of word problems

Let Us Solve
Q1Mala went to a book exhibition and bought 18 books. The shop was selling 3 books for ₹150. After buying the books, she still had ₹20 left. How much money did Mala have at the beginning?
Answer

Mala had ₹920 at the beginning.

Step 1. Number of sets = 18 ÷ 3 = 6 sets
Step 2. Cost of one set = ₹150
Step 3. Cost of 6 sets = 6 × 150
   6 × 15 = 90, so 6 × 150 = ₹900
Step 4. She still had ₹20 left over.
Step 5. Money at the start = 900 + 20 = ₹920
Q2A village sports club organises a women’s football tournament. They sold 57 tickets for ₹115 each. They had 3 teams joining the tournament, with each team paying a participation fee of ₹1,599. (a) How much money did the club collect in total from ticket sales and team participation fees?
Answer

The club collected ₹11,352 in all.

Money from tickets
Step 1. 57 tickets × ₹115 each
Step 2. 57 × 100 = 5,700
Step 3. 57 × 15 = 855
Step 4. 5,700 + 855 = ₹6,555
Money from participation fees
Step 1. 3 teams × ₹1,599 each
Step 2. Use the nearest multiple: 3 × 1,600 = 4,800
Step 3. That is ₹3 too much (one rupee per team).
Step 4. 4,800 − 3 = ₹4,797
Total collected
₹6,555 + ₹4,797 = ₹11,352
Q3(b) The teams paid ₹1,750 in total to rent the football ground and ₹1,129 for food and water. What were the total expenses on renting the ground and food and water?
Answer

The total expenses were ₹2,879.

Step 1. Ground rent = ₹1,750
Step 2. Food and water = ₹1,129
Step 3. Add the ones: 0 + 9 = 9
Step 4. Add the tens: 50 + 20 = 70
Step 5. Add the hundreds: 700 + 100 = 800
Step 6. Add the thousands: 1,000 + 1,000 = 2,000
Step 7. Total = 2,000 + 800 + 70 + 9 = ₹2,879
Q4Ananya is watching Republic Day celebrations on the city’s public ground. There are 12 rows of students sitting in front of her and 17 rows behind her. There are 18 students to her right and 22 students to her left. (a) How many rows of students are there in total? (b) How many students are there in Ananya’s row? (c) What is the total number of students on the ground?
Answer

(a) 30 rows (b) 41 students (c) 1,230 students.

(a) Total rows
Step 1. Rows in front = 12
Step 2. Rows behind = 17
Step 3. Ananya’s own row = 1
Step 4. Total = 12 + 17 + 1 = 30 rows
(b) Students in Ananya’s row
Step 1. Students to her right = 18
Step 2. Students to her left = 22
Step 3. Ananya herself = 1
Step 4. Total = 18 + 22 + 1 = 41 students
(c) Total students on the ground
Step 1. 30 rows, each with 41 students
Step 2. 30 × 41 = 30 × 40 + 30 × 1
Step 3. 1,200 + 30 = 1,230 students
Q5Multiply. (a) 67 × 78 (b) 34 × 56 (c) 45 × 263 (d) 86 × 542 (e) 432 × 107 (f) 310 × 120
Answer

All six products, each with a short method.

(a) 67 × 78 = 5,226
Step 1. 67 × 80 = 5,360
Step 2. That is two 67s too many: 2 × 67 = 134
Step 3. 5,360 − 134 = 5,226
(b) 34 × 56 = 1,904
Step 1. 34 × 50 = 1,700
Step 2. 34 × 6 = 204
Step 3. 1,700 + 204 = 1,904
(c) 45 × 263 = 11,835
Step 1. 263 × 40 = 10,520
Step 2. 263 × 5 = 1,315
Step 3. 10,520 + 1,315 = 11,835
(d) 86 × 542 = 46,612
Step 1. 542 × 80 = 43,360
Step 2. 542 × 6 = 3,252
Step 3. 43,360 + 3,252 = 46,612
(e) 432 × 107 = 46,224
Step 1. 432 × 100 = 43,200
Step 2. 432 × 7 = 3,024
Step 3. 43,200 + 3,024 = 46,224
(f) 310 × 120 = 37,200
Step 1. Set the zeros aside: 31 × 12 = 372
Step 2. One zero from 310 and one from 120 → two zeros
Step 3. Answer = 37,200
Q6If 67 × 67 = 4489, without multiplication find 67 × 68.
Answer

67 × 68 = 4,556.

67 × 68 = 67 × 67 + 67
= 4,489 + 67
= 4,556
Q7If 99 × 100 = 9900, without multiplication find 99 × 99.
Answer

99 × 99 = 9,801.

99 × 99 = 99 × 100 − 99
= 9,900 − 99
= 9,801

Chapter 6 of 15 – Maths

Also for This Chapter

NCERT Solutions Class 5 Maths Chapter 6 the Dairy Farm – Overview

ClassClass 5
SubjectMaths
Chapter6 – the Dairy Farm
Textbook pages70 – 91
Questions solved95
Session2027
FormatFull answers on this page + PDF

NCERT Solutions Class 5 Maths Chapter 6 – FAQs

Where can I download NCERT Solutions Class 5 Maths Chapter 6 the Dairy Farm PDF?

Read every answer on this page, or download the free PDF from the table at the top.

Is this for the 2027 session?

Yes, it follows the latest NCERT Class 5 Maths book for 2027.

How many questions are solved in NCERT Class 5 Maths Chapter 6?

All 95 questions of the chapter (textbook pages 70 – 91) – the in-text questions, activities and the end-of-chapter exercises.

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