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.
| Chapter | Download | |
|---|---|---|
| Solutions PDF (English medium) | The Dairy Farm | View 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
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.
| Shape | Number | Check |
|---|---|---|
| Green pentagon | 1 | (d) 2 × 1 = 2 |
| Orange diamond | 2 | (c) 6 × 2 = 12 |
| Pink circle | 3 | (a) 4 × 3 = 12 |
| Blue rectangle | 4 | (b) 4 × 4 = 16 |
| Yellow parallelogram | 6 | (e) 6 × 3 = 18 |
| Purple triangle | 12 | (f) 6 × 12 = 72 |
| White shape | 16 | (b) 4 × 4 = 16 |
| Blue half-circle | 18 | (f) 18 × 4 = 72 |
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).
Step 1. 50 × 2 = 100
Step 2. 3 × 2 = 6
Step 3. 100 + 6 = 106
All four arrangements hold 60 pouches. Only the way they are grouped changes.
20 × 3 = 60
6 × 10 = 60
5 × 12 = 60
You can make twelve different groupings of 60 pouches. Every pair of numbers that multiplies to 60 gives one.
| Number of groups | Group size | Total |
|---|---|---|
| 1 | 60 | 60 |
| 2 | 30 | 60 |
| 3 | 20 | 60 |
| 4 | 15 | 60 |
| 5 | 12 | 60 |
| 6 | 10 | 60 |
| 10 | 6 | 60 |
| 12 | 5 | 60 |
| 15 | 4 | 60 |
| 20 | 3 | 60 |
| 30 | 2 | 60 |
| 60 | 1 | 60 |
The number is 18.
Ones digit even → 18, 36
Not a multiple of 4 → 18
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.
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.
| Number | One way | Number | One way |
|---|---|---|---|
| 0 | not possible | 11 | 36 − 25 |
| 1 | 3 − 2 | 12 | 4 × 3 |
| 2 | 4 − 2 | 13 | 3 + 10 |
| 3 | 5 − 2 | 14 | 4 + 10 |
| 4 | 12 ÷ 3 | 15 | 5 + 10 |
| 5 | 3 + 2 | 16 | 4 + 12 |
| 6 | 2 × 3 | 17 | 5 + 12 |
| 7 | 5 + 2 | 18 | 36 ÷ 2 |
| 8 | 4 × 2 | 19 | not possible |
| 9 | 36 ÷ 4 | 20 | 5 × 4 |
| 10 | 12 − 2 |
The numbers you could not make with two grid numbers are 0 and 19. With three numbers and two operations, both become easy.
Step 1. 5 − 3 = 2
Step 2. 2 − 2 = 0
19 = 12 + 10 − 3
Step 1. 12 + 10 = 22
Step 2. 22 − 3 = 19
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.
| Number | Ways to make it |
|---|---|
| 1 | 3 − 2, 5 − 4, 4 − 3 |
| 2 | 4 − 2, 5 − 3, 12 − 10, 10 ÷ 5, 4 ÷ 2 |
| 3 | 5 − 2, 36 ÷ 12, 12 ÷ 4 |
| 4 | 12 ÷ 3, 100 ÷ 25 |
| 5 | 3 + 2, 25 ÷ 5, 10 − 5, 10 ÷ 2 |
| 6 | 4 + 2, 2 × 3, 10 − 4, 12 ÷ 2 |
| 7 | 5 + 2, 3 + 4, 12 − 5, 10 − 3 |
| 8 | 5 + 3, 10 − 2, 4 × 2, 12 − 4 |
| 9 | 12 − 3, 36 ÷ 4, 4 + 5 |
| 10 | 12 − 2, 100 ÷ 10, 5 × 2 |
| 11 | 36 − 25 only |
| 12 | 2 + 10, 4 × 3, 36 ÷ 3 |
| 13 | 3 + 10, 25 − 12 |
| 14 | 2 + 12, 4 + 10 |
| 15 | 5 + 10, 3 + 12, 25 − 10, 5 × 3 |
| 16 | 4 + 12 only |
| 17 | 5 + 12 only |
| 18 | 36 ÷ 2 only |
| 20 | 5 × 4, 25 − 5, 100 ÷ 5, 2 × 10 |
Order of Numbers in Multiplication — Page 72Daljeet Kaur arranges the butter packets
(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
Both arrangements in every pair hold the same number of packets. Here are all the answers.
| Case | First way | Second way | Packets |
|---|---|---|---|
| (a) | 2 × 3 | 3 × 2 | 6 |
| (b) | 5 × 8 | 8 × 5 | 40 |
| 6 groups of 13 | 6 × 13 | 13 × 6 | 78 |
| (e) | 10 × 5 | 5 × 10 | 50 |
| (f) | 8 × 20 | 20 × 8 | 160 |
| (g) | 12 × 9 | 9 × 12 | 108 |
The pattern: the number of groups and the group size are swapped, but the total never changes.
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.
0 × 9 = 0
So 9 × 0 = 0 × 9 ✓
Patterns in Multiplication by 10s and 100s — Pages 72–74Filling the place value tables
Here are all the answers.
| Question | Answer | Think of it as |
|---|---|---|
| a) 4 × 10 | 40 | 4 tens |
| b) 20 × 10 | 200 | 20 tens |
| c) 10 × 40 | 400 | 40 tens |
| d) 10 × 10 | 100 | 10 tens (given) |
| e) 20 × 50 | 1,000 | 2 × 5 × 10 × 10 = 10 × 100 |
| f) 80 × 10 | 800 | 80 tens |
| g) 3 × 100 | 100 × 3 = 300 | 3 hundreds (given) |
| h) 8 × 100 | 100 × 8 = 800 | 8 hundreds |
| i) 10 × 100 | 100 × 10 = 1,000 | 10 hundreds |
All six answers, with the easy way to get each one.
| Question | Break it up | Answer |
|---|---|---|
| 100 × 90 | 1 × 9 × 100 × 10 = 9 × 1,000 | 9,000 |
| 400 × 10 | 4 × 100 × 10 = 4 × 1,000 | 4,000 |
| 60 × 50 | 6 × 5 × 10 × 10 = 30 × 100 | 3,000 |
| 30 × 20 | 3 × 2 × 10 × 10 = 6 × 100 | 600 (given) |
| 700 × 4 | 7 × 4 × 100 = 28 × 100 | 2,800 |
| 10 × 45 | 45 tens | 450 |
| Problem | Th | H | T | O |
|---|---|---|---|---|
| 10 × 45 = | ||||
| 30 × 20 = | 6 | 0 | 0 | |
| 400 × 10 = | ||||
| 700 × 8 = | ||||
| 100 × 90 = | 9 | 0 | 0 | 0 |
Write 4 in the hundreds column, 5 in the tens column and 0 in the ones column. The thousands column stays empty.
| Number | Th | H | T | O |
|---|---|---|---|---|
| 450 | 4 | 5 | 0 |
| Problem | Th | H | T | O |
|---|---|---|---|---|
| 10 × 45 = | ||||
| 30 × 20 = | 6 | 0 | 0 | |
| 400 × 10 = | ||||
| 700 × 8 = | ||||
| 100 × 90 = | 9 | 0 | 0 | 0 |
The completed table.
| Problem | Th | H | T | O | Answer |
|---|---|---|---|---|---|
| 10 × 45 | 4 | 5 | 0 | 450 | |
| 30 × 20 | 6 | 0 | 0 | 600 (given) | |
| 400 × 10 | 4 | 0 | 0 | 0 | 4,000 |
| 700 × 8 | 5 | 6 | 0 | 0 | 5,600 |
| 100 × 90 | 9 | 0 | 0 | 0 | 9,000 (given) |
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.
| Problem | Th | H | T | O |
|---|---|---|---|---|
| 60 × 50 = | ||||
| 220 × 20 = | ||||
| 11 × 300 = |
| Problem | Th | H | T | O |
|---|---|---|---|---|
| 80 × 90 = | ||||
| 10 × 63 = | ||||
| 40 × 12 = |
Both tables, completed.
| Problem | Th | H | T | O | Answer |
|---|---|---|---|---|---|
| 60 × 50 | 3 | 0 | 0 | 0 | 3,000 |
| 220 × 20 | 4 | 4 | 0 | 0 | 4,400 |
| 11 × 300 | 3 | 3 | 0 | 0 | 3,300 |
| 80 × 90 | 7 | 2 | 0 | 0 | 7,200 |
| 10 × 63 | 6 | 3 | 0 | 630 | |
| 40 × 12 | 4 | 8 | 0 | 480 |
Every digit shifts three places to the left, and three zeros appear at the end.
5 × 1,000 = 5 thousand = 5,000
10 × 1,000 = 10 thousand = 10,000
20 × 1,000 = 20 thousand = 20,000
| Problem | TTh | Th | H | T | O |
|---|---|---|---|---|---|
| 2 × 1,000 = | 2 | 0 | 0 | 0 | |
| 5 × 1,000 = | 5 | 0 | 0 | 0 | |
| 10 × 1,000 = | 1 | 0 | 0 | 0 | 0 |
| 20 × 1,000 = | 2 | 0 | 0 | 0 | 0 |
| 3 × 5,000 = | |||||
| 8 × 3,000 = | |||||
| 5 × 7,000 = |
The completed table.
| Problem | TTh | Th | H | T | O | Answer |
|---|---|---|---|---|---|---|
| 2 × 1,000 | 2 | 0 | 0 | 0 | 2,000 (given) | |
| 5 × 1,000 | 5 | 0 | 0 | 0 | 5,000 (given) | |
| 10 × 1,000 | 1 | 0 | 0 | 0 | 0 | 10,000 (given) |
| 20 × 1,000 | 2 | 0 | 0 | 0 | 0 | 20,000 (given) |
| 3 × 5,000 | 1 | 5 | 0 | 0 | 0 | 15,000 |
| 8 × 3,000 | 2 | 4 | 0 | 0 | 0 | 24,000 |
| 5 × 7,000 | 3 | 5 | 0 | 0 | 0 | 35,000 |
| Problem | TTh | Th | H | T | O |
|---|---|---|---|---|---|
| 20 × 100 = | |||||
| 40 × 500 = | |||||
| 60 × 300 = | |||||
| 600 × 30 = | |||||
| 80 × 900 = | |||||
| 70 × 600 = | |||||
| 5 × 7,000 = |
The completed table.
| Problem | TTh | Th | H | T | O | Answer |
|---|---|---|---|---|---|---|
| 20 × 100 | 2 | 0 | 0 | 0 | 2,000 | |
| 40 × 500 | 2 | 0 | 0 | 0 | 0 | 20,000 |
| 60 × 300 | 1 | 8 | 0 | 0 | 0 | 18,000 |
| 600 × 30 | 1 | 8 | 0 | 0 | 0 | 18,000 |
| 80 × 900 | 7 | 2 | 0 | 0 | 0 | 72,000 |
| 70 × 600 | 4 | 2 | 0 | 0 | 0 | 42,000 |
| 5 × 7,000 | 3 | 5 | 0 | 0 | 0 | 35,000 |
Many Ways to Multiply — Page 74Five children find 18 × 5
18 × 5 = 90.
Step 1. Half of 18 is 9.
Step 2. Double of 5 is 10.
Step 3. 9 × 10 = 90
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.
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
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.
Double 3 → 6, halve 18 → 9
6 × 9 = 54 ✓
11 × 10 = 110.
Step 1. Half of 22 = 11
Step 2. Double of 5 = 10
Step 3. 11 × 10 = 110 packets
Halve the first number, double the second, then multiply.
| Problem | Half | Double | New problem | Answer |
|---|---|---|---|---|
| 14 × 3 | 7 | 6 | 7 × 6 | 42 |
| 38 × 5 | 19 | 10 | 19 × 10 | 190 |
| 16 × 4 | 8 | 8 | 8 × 8 | 64 |
| 35 × 14 | 7 (half of 14) | 70 (double of 35) | 70 × 7 | 490 |
Because doubling 5 gives 10, and doubling 25 twice gives 100 — and multiplying by 10 or 100 is the easiest job in arithmetic.
18 × 5 → 9 × 10 = 90
Example with 25
16 × 25 → 8 × 50 = 4 × 100 = 400
All six, each shown as a single easy step.
| Problem | Halve | Double | Becomes | Answer |
|---|---|---|---|---|
| 1) 5 × 18 | 18 → 9 | 5 → 10 | 10 × 9 | 90 |
| 2) 50 × 28 | 28 → 14 | 50 → 100 | 100 × 14 | 1,400 |
| 3) 15 × 22 | 22 → 11 | 15 → 30 | 30 × 11 | 330 |
| 4) 25 × 12 | 12 → 6 | 25 → 50 | 50 × 6 | 300 |
| 5) 12 × 45 | 12 → 6 | 45 → 90 | 6 × 90 | 540 |
| 6) 16 × 45 | 16 → 8 | 45 → 90 | 8 × 90 | 720 |
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 example | Halve and double | Becomes | Product |
|---|---|---|---|
| 5 × 24 | 24 → 12, 5 → 10 | 10 × 12 | 120 |
| 25 × 16 | 16 → 8, 25 → 50; again 8 → 4, 50 → 100 | 100 × 4 | 400 |
| 15 × 14 | 14 → 7, 15 → 30 | 30 × 7 | 210 |
| 5 × 36 | 36 → 18, 5 → 10 | 10 × 18 | 180 |
| 50 × 18 | 18 → 9, 50 → 100 | 100 × 9 | 900 |
Nearest Multiple — Page 76Jump to a friendly number, then adjust
Because the picture shows 4 rows of 20 with one column rubbed out, and that column holds 4 packets.
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
Because 21 columns is 20 columns plus one extra, and that extra column holds 14 packets.
Step 1. 14 × 20 = 280
Step 2. One extra column = 14
Step 3. 280 + 14 = 294
choose problems where one number is just below or just above a ten, a hundred or a nice multiple.
| My example | Nearest multiple | Adjust | Product |
|---|---|---|---|
| 9 × 32 | 10 × 32 = 320 | − 32 | 288 |
| 99 × 7 | 100 × 7 = 700 | − 7 | 693 |
| 21 × 15 | 20 × 15 = 300 | + 15 | 315 |
| 49 × 6 | 50 × 6 = 300 | − 6 | 294 |
| 101 × 8 | 100 × 8 = 800 | + 8 | 808 |
All six, with the friendly number named each time.
| Problem | Nearest multiple | Adjustment | Answer |
|---|---|---|---|
| 1) 7 × 52 | 7 × 50 = 350 | + 7 × 2 = 14 | 364 |
| 2) 12 × 28 | 12 × 30 = 360 | − 12 × 2 = 24 | 336 |
| 3) 75 × 31 | 75 × 30 = 2,250 | + 75 | 2,325 |
| 4) 99 × 15 | 100 × 15 = 1,500 | − 15 | 1,485 |
| 5) 8 × 25 | 10 × 25 = 250 | − 2 × 25 = 50 | 200 |
| 6) 22 × 42 | 22 × 40 = 880 | + 22 × 2 = 44 | 924 |
Let Us Solve — Page 77Word problems: use the strategies flexibly
1,470 people can sit in the auditorium.
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
Priya will jog 124 kilometres in 31 days.
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
The school received 1,728 books.
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
She would need 32 metres of cloth.
Step 2. Cloth needed = 2 × 16 m
Step 3. 2 × 16 = 32 metres
The cows produce 145 litres of milk each day.
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
5,346 kg of fodder is needed every day.
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
The family produces 420 kg of kitchen waste in a year.
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
35 (30 + 5)
× 12 (10 + 2)
10 (2 × 5)
60 (2 × 30)
50 (10 × 5)
300 (10 × 30)
420
35 (30 + 5)
× 12 (10 + 2)
60 + 10 = 70 (2 × 35)
300 + 50 = 350 (10 × 35)
= 420
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 lines | John 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 420 | Total 420 |
The family saves ₹3,600 in a year.
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
| × | 30 | 2 |
| 8 | ||
32 × 8 = 256. Here is every blank filled in.
| × | 30 | 2 |
|---|---|---|
| 8 | 240 | 16 |
| Total | 240 + 16 = 256 | |
32 (30 + 2)
× 8
Step 1. 8 × 2 = 16
Step 2. 8 × 30 = 240
Step 3. 16 + 240 = 256
32 (30 + 2)
× 8
240 + 16 = 256
| × | 60 | 9 |
| 40 | ||
| 5 | ||
| 2700 | 405 | |
| 3105 | ||
69 × 45 = 3,105. Every blank filled in.
| × | 60 | 9 | Row total |
|---|---|---|---|
| 40 | 2,400 | 360 | 2,760 |
| 5 | 300 | 45 | 345 |
| Column total | 2,700 | 405 | 3,105 |
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
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
Nida’s solution (12 × 35 kg, from the kitchen-waste problem):
| × | 30 kg | 5 kg |
| 10 | 300 | 50 |
| 2 | 60 | 10 |
| 360 | 60 | |
| 420 | ||
a) 78 × 4
| × | ||
b) 83 × 9
| × | ||
c) 67 × 28
| × | ||
d) 53 × 37
| × | ||
Nida’s way is to draw a grid, split each number into its place values, multiply every box, then add.
a) 78 × 4 = 312
| × | 70 | 8 |
|---|---|---|
| 4 | 280 | 32 |
| Total | 280 + 32 = 312 | |
b) 83 × 9 = 747
| × | 80 | 3 |
|---|---|---|
| 9 | 720 | 27 |
| Total | 720 + 27 = 747 | |
c) 67 × 28 = 1,876
| × | 60 | 7 | Row total |
|---|---|---|---|
| 20 | 1,200 | 140 | 1,340 |
| 8 | 480 | 56 | 536 |
| Total | 1,340 + 536 = 1,876 | ||
d) 53 × 37 = 1,961
| × | 50 | 3 | Row total |
|---|---|---|---|
| 30 | 1,500 | 90 | 1,590 |
| 7 | 350 | 21 | 371 |
| Total | 1,590 + 371 = 1,961 | ||
Kanti’s way is to write every small piece on its own line, smallest first, then add them all.
94 (90 + 4) × 5
Step 1. 5 × 4 = 20
Step 2. 5 × 90 = 450
Step 3. 20 + 450 = 470
49 (40 + 9) × 6
Step 1. 6 × 9 = 54
Step 2. 6 × 40 = 240
Step 3. 54 + 240 = 294
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
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
John’s way is one line for each digit of the second number, with the pieces of that line already added together.
Step 1. 3 × 86 → 240 + 18 = 258
Step 1. 7 × 72 → 490 + 14 = 504
Step 1. 6 × 94 → 540 + 24 = 564
Step 2. 30 × 94 → 2,700 + 120 = 2,820
Step 3. 564 + 2,820 = 3,384
Step 1. 2 × 66 → 120 + 12 = 132
Step 2. 20 × 66 → 1,200 + 120 = 1,320
Step 3. 132 + 1,320 = 1,452
48 people are watching. After 3 more rows fill up, there will be 84 people.
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
Runs in 4s = 96. Runs in 6s = 108. Total runs in the two innings = 461.
Step 1. 24 fours = 24 × 4
Step 2. 24 × 4 = 96 runs
Step 1. 18 sixes = 18 × 6
Step 2. 18 × 6 = 108 runs
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
Anjali should give ₹783 to the shopkeeper.
Step 1. 15 bulbs × ₹25 each
Step 2. 15 × 25 = 10 × 25 + 5 × 25 = 250 + 125 = ₹375
Step 1. 12 tube lights × ₹34 each
Step 2. 12 × 34 = 10 × 34 + 2 × 34
Step 3. 340 + 68 = ₹408
₹375 + ₹408 = ₹783
He earned ₹9,800.
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
The library has 13,932 books.
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
The dairy cooperative gets milk from at least 1,072 cows.
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
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.
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
The cooperative receives 5,889 litres of milk from Gir cows every day.
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
The cooperative earns ₹71,750 in a month.
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
× 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
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.
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
Nida’s grid: split both numbers into place values, multiply every box, add everything.
a) 548 × 6 = 3,288
| × | 500 | 40 | 8 |
|---|---|---|---|
| 6 | 3,000 | 240 | 48 |
b) 682 × 3 = 2,046
| × | 600 | 80 | 2 |
|---|---|---|---|
| 3 | 1,800 | 240 | 6 |
c) 324 × 18 = 5,832
| × | 300 | 20 | 4 | Row total |
|---|---|---|---|---|
| 10 | 3,000 | 200 | 40 | 3,240 |
| 8 | 2,400 | 160 | 32 | 2,592 |
d) 507 × 23 = 11,661
| × | 500 | 0 | 7 | Row total |
|---|---|---|---|---|
| 20 | 10,000 | 0 | 140 | 10,140 |
| 3 | 1,500 | 0 | 21 | 1,521 |
e) 190 × 65 = 12,350
| × | 100 | 90 | Row total |
|---|---|---|---|
| 60 | 6,000 | 5,400 | 11,400 |
| 5 | 500 | 450 | 950 |
John’s way: one line for each digit of the multiplier, with that line’s pieces already added.
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
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
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
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
Step 1. 5 × 592 → 2,500 + 450 + 10 = 2,960
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
806 × 9 = 7,254; 455 × 26 = 11,830; 143 × 208 = 29,744. Here is every box filled.
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
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
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
Row 1 — the 8: 8 × 450 = 3,600
Row 2 — the 3 tens: 30 × 450 = 13,500
Total = 3,600 + 13,500 = 17,100
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
Row 1 — the 3: 3 × 302 = 906
Row 2 — the 1 ten: 10 × 302 = 3,020
Total = 906 + 3,020 = 3,926
Row 1 — the 4: 4 × 604 = 2,416
Row 2 — the 5 tens: 50 × 604 = 30,200
Total = 2,416 + 30,200 = 32,616
Row 1 — the 3: 3 × 112 = 336
Row 2 — the 2 tens: 20 × 112 = 2,240
Total = 336 + 2,240 = 2,576
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?
46
× 59
2,000
300
360
54
2,714
Asma is correct. 46 × 59 = 2,714.
| Her line | Where it comes from | Check |
|---|---|---|
| 2,000 | 50 × 40 | 2,000 ✓ |
| 300 | 50 × 6 | 300 ✓ |
| 360 | 9 × 40 | 360 ✓ |
| 54 | 9 × 6 | 54 ✓ |
2,300 + 360 = 2,660
2,660 + 54 = 2,714 ✓
203
× 54
80 + 12 = 92
100 + 15 = 115
= 135
Pankaj is wrong. The correct answer is 203 × 54 = 10,962. He made three mistakes.
- 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.
- He used 5 instead of 50. The 5 in 54 is 5 tens, so the second row must be 50 × 203.
- His addition is wrong too: 92 + 115 = 207, not 135.
4 × 203 = 800 + 0 + 12 = 812
50 × 203 = 10,000 + 0 + 150 = 10,150
812 + 10,150 = 10,962
38
× 150
1,500 + 400 = 1,900
3,000 + 800 = 3,800
= 5,700
Lado is correct. 38 × 150 = 5,700.
| Her row | Where it comes from | Row total |
|---|---|---|
| 1,500 + 400 | 50 × 30 and 50 × 8 | 1,900 (= 50 × 38) |
| 3,000 + 800 | 100 × 30 and 100 × 8 | 3,800 (= 100 × 38) |
193
× 272
200 + 180 + 6 = 386
700 + 630 + 21 = 1,351
20,000 + 18,000 + 600 = 38,600
= 40,337
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.
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
(e) Asher’s solution for 626 × 323 (carries 1, 1, 1 in the top row)
| Th | H | T | O | |
|---|---|---|---|---|
| 1 | 1 | 1 | ||
| 6 | 2 | 6 | ||
| × | 3 | 2 | 3 | |
| 1 | 8 | 7 | 8 | |
| 1 | 2 | 5 | 2 | |
| + | 1 | 8 | 7 | 8 |
| 5 | 0 | 1 | 8 |
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.)
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
| Top of the box | Problems in the box |
|---|---|
| 12 × 17 | 11 × 18 · 6 × 34 |
| 26 × 11 | 26 × 10 and 26 × 1 · 20 × 11 and 6 × 11 |
| 18 × 4 | 9 × 8 · 20 × 4 − 8 |
| 55 × 9 | 50 × 9 and 5 × 9 · 54 × 10 · 55 × 10 − 55 |
| 101 × 42 | 100 × 42 and 100 · 100 × 42 and 42 |
| 247 × 8 | 250 × 8 − 24 · 247 × 10 − 247 |
| 1001 × 5 | 1,000 × 6 · 1,000 × 5 and 5 |
| 1999 × 2 | 2,000 × 2 − 4 · 2,000 × 2 − 2 |
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.
| Box | Option | Same? | Reason |
|---|---|---|---|
| 12 × 17 | 11 × 18 | No | Neither number was halved or doubled; this is a different product |
| 12 × 17 | 6 × 34 | Yes | 12 halved is 6, 17 doubled is 34 |
| 26 × 11 | 26 × 10 and 26 × 1 | Yes | 11 = 10 + 1 |
| 26 × 11 | 20 × 11 and 6 × 11 | Yes | 26 = 20 + 6 |
| 18 × 4 | 9 × 8 | Yes | 18 halved is 9, 4 doubled is 8 |
| 18 × 4 | 20 × 4 − 8 | Yes | 18 is 2 less than 20, and 2 × 4 = 8 |
| 55 × 9 | 50 × 9 and 5 × 9 | Yes | 55 = 50 + 5 |
| 55 × 9 | 54 × 10 | No | You may not change both numbers like that |
| 55 × 9 | 55 × 10 − 55 | Yes | 9 is one less than 10, so take away one 55 |
| 101 × 42 | 100 × 42 and 100 | No | The extra piece is one 42, not one 100 |
| 101 × 42 | 100 × 42 and 42 | Yes | 101 = 100 + 1, so add one 42 |
| 247 × 8 | 250 × 8 − 24 | Yes | 247 is 3 less than 250, and 3 × 8 = 24 |
| 247 × 8 | 247 × 10 − 247 | No | That gives 247 × 9, not 247 × 8 |
| 1001 × 5 | 1,000 × 6 | No | Both numbers were changed with nothing to balance it |
| 1001 × 5 | 1,000 × 5 and 5 | Yes | 1001 = 1000 + 1, so add one 5 |
| 1999 × 2 | 2,000 × 2 − 4 | No | 1999 is only 1 less than 2000, so we must take away one 2, not 4 |
| 1999 × 2 | 2,000 × 2 − 2 | Yes | 1999 = 2000 − 1, so take away one 2 |
All three become easy if you climb to 100, 500 or 1,000 by doubling.
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
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
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
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
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
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
Step 1. Double 50 to 100, halve 78 to 39 → 100 × 39
Step 2. 100 × 39 = 3,900
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
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
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 example | The easy way | Product |
|---|---|---|
| 32 × 25 | 16 × 50 = 8 × 100 | 800 |
| 98 × 45 | 100 × 45 − 2 × 45 = 4,500 − 90 | 4,410 |
| 64 × 125 | 32 × 250 = 16 × 500 = 8 × 1,000 | 8,000 |
| 1,001 × 7 | 1,000 × 7 + 7 | 7,007 |
| 45 × 20 | 90 × 10 | 900 |
(b) 408 (c) 374 (d) 368. You do not need to multiply again — just add or take away one whole group.
- (b) 17 × 24. This is one more group of 17 than 17 × 23. So 391 + 17 = 408.
- (c) 17 × 22. This is one group of 17 fewer. So 391 − 17 = 374.
- (d) 16 × 23. Here the other number went down by 1, so we lose one group of 23. So 391 − 23 = 368.
(f) 162 (g) 252 (h) 972 (i) 414.
- (f) 18 × 9. 18 is 8 + 10, so add ten more 9s. 72 + 90 = 162.
- (g) 28 × 9. 28 is 18 + 10, so add ten more 9s again. 162 + 90 = 252. (Or from 8 × 9: 72 + 180 = 252.)
- (h) 108 × 9. 108 is 8 + 100, so add a hundred 9s. 72 + 900 = 972.
- (i) 18 × 23. Go back to 17 × 23 = 391. One more row of 23 gives 391 + 23 = 414.
Add 17. 17 × 24 has one more column than 17 × 23, and each column has 17 squares. So 17 × 24 = 391 + 17 = 408.
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
(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.
(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.
(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.
Round each number to a friendly one, then multiply.
| Problem | Round it to | Estimate | Matches | Exact answer |
|---|---|---|---|---|
| 25 × 31 | 25 × 30 | 750 | 750 | 775 |
| 132 × 19 | 130 × 20 | 2,600 | 2,600 | 2,508 |
| 101 × 11 | 100 × 10 | 1,000 | 1,000 | 1,111 |
| 248 × 49 | 250 × 50 | 12,500 | 12,500 | 12,152 |
| 12 × 25 | 12 × 25 | 300 | 300 | 300 |
The King’s Reward — Pages 88–89Three ministers, three choices of gold
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.
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.
Choice 1: 5 → 10 → 20 → 40
Choice 2: 3 → 9 → 27 → 81
Choice 3: 1 → 5 → 25 → 125
Already the smallest start is winning.
Minister 3 received the most: 78,125 gold coins. Minister 1 got 640 and Minister 2 got 6,561.
| Day | Minister 1 (start 5, double) | Minister 2 (start 3, triple) | Minister 3 (start 1, × 5) |
|---|---|---|---|
| Start | 5 | 3 | 1 |
| 1 | 10 | 9 | 5 |
| 2 | 20 | 27 | 25 |
| 3 | 40 | 81 | 125 |
| 4 | 80 | 243 | 625 |
| 5 | 160 | 729 | 3,125 |
| 6 | 320 | 2,187 | 15,625 |
| 7 | 640 | 6,561 | 78,125 |
Multiplication Patterns — Pages 89–90How the product changes, and number-pair grids
3) 16 × 22 = 352 and 4) 32 × 44 = 1,408.
| Problem | What changed | Effect on the product | Answer |
|---|---|---|---|
| 16 × 44 = 704 | the original | — | 704 |
| 1) 8 × 88 | 16 halved, 44 doubled | no change | 704 |
| 2) 8 × 22 | both halved | one quarter of 704 | 176 |
| 3) 16 × 22 | 44 halved only | half of 704 | 352 |
| 4) 32 × 44 | 16 doubled only | double of 704 | 1,408 |
1) 96 2) 384 3) 1,536 4) 192
| Problem | What changed | Effect on 384 | Answer |
|---|---|---|---|
| 12 × 32 = 384 | the original | — | 384 |
| 1) 6 × 16 | both halved | one quarter | 96 |
| 2) 24 × 16 | 12 doubled, 32 halved | no change | 384 |
| 3) 24 × 64 | both doubled | four times | 1,536 |
| 4) 12 × 16 | 32 halved only | half | 192 |
1111 × 1111 = 12,34,321.
11 × 11 = 121
111 × 111 = 12,321
1111 × 1111 = 12,34,321
(and 11111 × 11111 = 12,34,54,321)
11 × 54 = 594 and 11 × 82 = 902.
- 11 × 54. Split 54 into 5 and 4. Write 5, then 5 + 4 = 9, then 4. That gives 594.
- 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.
45 × 45 = 2,025 and 55 × 55 = 3,025.
| Problem | Front part | End | Answer |
|---|---|---|---|
| 25 × 25 | 2 × 3 = 6 | 25 | 625 |
| 35 × 35 | 3 × 4 = 12 | 25 | 1,225 |
| 45 × 45 | 4 × 5 = 20 | 25 | 2,025 |
| 55 × 55 | 5 × 6 = 30 | 25 | 3,025 |
1,234 × 9 + 4 = 11,110.
- Multiply first. 1,234 × 9. Use the nearest multiple: 1,234 × 10 = 12,340, then take away one 1,234.
- 12,340 − 1,234 = 11,106.
- Now add 4. 11,106 + 4 = 11,110.
| 8 | 35 | 75 |
| 32 | 62 | 13 |
| 66 | 11 | 14 |
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
Mala had ₹920 at the beginning.
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
The club collected ₹11,352 in all.
Step 1. 57 tickets × ₹115 each
Step 2. 57 × 100 = 5,700
Step 3. 57 × 15 = 855
Step 4. 5,700 + 855 = ₹6,555
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
₹6,555 + ₹4,797 = ₹11,352
The total expenses were ₹2,879.
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
(a) 30 rows (b) 41 students (c) 1,230 students.
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
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
Step 1. 30 rows, each with 41 students
Step 2. 30 × 41 = 30 × 40 + 30 × 1
Step 3. 1,200 + 30 = 1,230 students
All six products, each with a short method.
Step 1. 67 × 80 = 5,360
Step 2. That is two 67s too many: 2 × 67 = 134
Step 3. 5,360 − 134 = 5,226
Step 1. 34 × 50 = 1,700
Step 2. 34 × 6 = 204
Step 3. 1,700 + 204 = 1,904
Step 1. 263 × 40 = 10,520
Step 2. 263 × 5 = 1,315
Step 3. 10,520 + 1,315 = 11,835
Step 1. 542 × 80 = 43,360
Step 2. 542 × 6 = 3,252
Step 3. 43,360 + 3,252 = 46,612
Step 1. 432 × 100 = 43,200
Step 2. 432 × 7 = 3,024
Step 3. 43,200 + 3,024 = 46,224
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
67 × 68 = 4,556.
= 4,489 + 67
= 4,556
99 × 99 = 9,801.
= 9,900 − 99
= 9,801
Chapter 6 of 15 – Maths
- Previous: Chapter 5 Far and Near
- Next: Chapter 7 Shapes and Patterns
- All chapters: NCERT Solutions Class 5 Maths
Also for This Chapter
NCERT Solutions Class 5 Maths Chapter 6 the Dairy Farm – Overview
| Class | Class 5 |
| Subject | Maths |
| Chapter | 6 – the Dairy Farm |
| Textbook pages | 70 – 91 |
| Questions solved | 95 |
| Session | 2027 |
| Format | Full 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.
How should I use these solutions?
Read the chapter in the NCERT book first, attempt the questions yourself, then check your answers here.