NCERT Solutions for Class 4 Maths Chapter 7 the Cleanest Village – 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.
Daisy and Lou go on a school trip to Mawlynnong, Asia’s cleanest village. On the way we add and subtract in columns, and learn to regroup 10 ones as 1 ten and 10 tens as 1 hundred.
NCERT Solutions for Class 4 Maths Chapter 7 the Cleanest Village 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.
NCERT Solutions for Class 4 Maths Chapter 7 the Cleanest Village – Questions and Answers
All 107 questions of the chapter (textbook pages 95 – 114) 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.
In-text Questions — Page 97Daisy and Lou Go Shopping
Q12 kg of beans — ______
Fruit / vegetable
Cost for 1 kg
Custard apple
₹ 45
Beans
₹ 95
Radish
₹ 23
Onion
₹ 32
Potato
₹ 37
Yam
₹ 45
Sapota
₹ 70
Papaya
₹ 65
Banana
₹ 55
Sapan Dada’s price list, as printed on page 96.
Answer
The cost is ₹190.
1 kg of beans = ₹95 2 kg = ₹95 + ₹95 Total = ₹190
The working, written in columns.
Q21 kg of custard apple and 1 kg of sapota — ______
Fruit / vegetable
Cost for 1 kg
Custard apple
₹ 45
Beans
₹ 95
Radish
₹ 23
Onion
₹ 32
Potato
₹ 37
Yam
₹ 45
Sapota
₹ 70
Papaya
₹ 65
Banana
₹ 55
Sapan Dada’s price list, as printed on page 96.
Answer
The cost is ₹115.
Custard apple = ₹45 Sapota = ₹70 ₹45 + ₹70 Total = ₹115
The working, written in columns.
Q31 kg of onion and 1 kg of potato — ______
Fruit / vegetable
Cost for 1 kg
Custard apple
₹ 45
Beans
₹ 95
Radish
₹ 23
Onion
₹ 32
Potato
₹ 37
Yam
₹ 45
Sapota
₹ 70
Papaya
₹ 65
Banana
₹ 55
Sapan Dada’s price list, as printed on page 96.
Answer
The cost is ₹69.
Onion = ₹32 Potato = ₹37 ₹32 + ₹37 Total = ₹69
The working, written in columns.
Q41 kg of radish and 1 kg of yam — ______
Fruit / vegetable
Cost for 1 kg
Custard apple
₹ 45
Beans
₹ 95
Radish
₹ 23
Onion
₹ 32
Potato
₹ 37
Yam
₹ 45
Sapota
₹ 70
Papaya
₹ 65
Banana
₹ 55
Sapan Dada’s price list, as printed on page 96.
Answer
The cost is ₹68.
Radish = ₹23 Yam = ₹45 ₹23 + ₹45 Total = ₹68
The working, written in columns.
Q52 kg of radish and 2 kg of papaya — ______
Fruit / vegetable
Cost for 1 kg
Custard apple
₹ 45
Beans
₹ 95
Radish
₹ 23
Onion
₹ 32
Potato
₹ 37
Yam
₹ 45
Sapota
₹ 70
Papaya
₹ 65
Banana
₹ 55
Sapan Dada’s price list, as printed on page 96.
Answer
The cost is ₹176.
2 kg radish = ₹23 + ₹23 = ₹46 2 kg papaya = ₹65 + ₹65 = ₹130 ₹46 + ₹130 Total = ₹176
The working, written in columns.
Q62 kg of onion and 2 kg of potato — ______
Fruit / vegetable
Cost for 1 kg
Custard apple
₹ 45
Beans
₹ 95
Radish
₹ 23
Onion
₹ 32
Potato
₹ 37
Yam
₹ 45
Sapota
₹ 70
Papaya
₹ 65
Banana
₹ 55
Sapan Dada’s price list, as printed on page 96.
Answer
The cost is ₹138.
2 kg onion = ₹32 + ₹32 = ₹64 2 kg potato = ₹37 + ₹37 = ₹74 ₹64 + ₹74 Total = ₹138
The working, written in columns.
Q7What do you notice about these two costs?
Fruit / vegetable
Cost for 1 kg
Custard apple
₹ 45
Beans
₹ 95
Radish
₹ 23
Onion
₹ 32
Potato
₹ 37
Yam
₹ 45
Sapota
₹ 70
Papaya
₹ 65
Banana
₹ 55
Sapan Dada’s price list, as printed on page 96.
Answer
The two costs are ₹69 and ₹138. The second one is exactly double the first.
1 kg onion + 1 kg potato = ₹32 + ₹37 = ₹69 2 kg onion + 2 kg potato = ₹64 + ₹74 = ₹138 ₹69 + ₹69 = ₹138
Q8Their mother buys things for ₹163. What might she have bought? There is more than one possibility.
Q1Help Udaya Didi find the missing number(s) on this bill card.
Cost –
₹185
Paid –
₹200
Balance –
__________
The card as it is printed on page 98.
Answer
The balance is ₹15.
Balance = Paid − Cost = ₹200 − ₹185 = ₹15
The working, written in columns.
Cost –
₹185
Paid –
₹200
Balance –
₹15
The same card with the missing number filled in.
Q2Help Udaya Didi find the missing number(s) on this bill card.
Cost –
__________
Paid –
₹200
Balance –
₹0
The card as it is printed on page 98.
Answer
The cost is ₹200.
Balance = 0, so nothing came back. Cost = Paid = ₹200
Cost –
₹200
Paid –
₹200
Balance –
₹0
The same card with the missing number filled in.
Q3Help Udaya Didi find the missing number(s) on this bill card.
Cost –
₹435
Paid –
₹500
Balance –
__________
The card as it is printed on page 98.
Answer
The balance is ₹65.
₹500 − ₹435 = ₹65
The working, written in columns.
Cost –
₹435
Paid –
₹500
Balance –
₹65
The same card with the missing number filled in.
Q4Help Udaya Didi find the missing number(s) on this bill card.
Cost –
₹149
Paid –
₹500
Balance –
__________
The card as it is printed on page 98.
Answer
The balance is ₹351.
₹500 − ₹149 = ₹351
The working, written in columns.
Cost –
₹149
Paid –
₹500
Balance –
₹351
The same card with the missing number filled in.
Q5Help Udaya Didi find the missing number(s) on this bill card.
Cost –
₹46
Paid –
__________
Balance –
__________
The card as it is printed on page 98.
Answer
The cost is fixed, but the money paid is our choice. Any note or coins worth ₹46 or more will do.
Sample answer: the customer pays a ₹50 note.
Balance = ₹50 − ₹46 = ₹4
The working, written in columns.
Cost –
₹46
Paid –
₹50
Balance –
₹4
One correct way to fill the card.
Q6Help Udaya Didi find the missing number(s) on this bill card.
Cost –
__________
Paid –
₹200
Balance –
₹75
The card as it is printed on page 98.
Answer
The cost is ₹125.
Cost = Paid − Balance = ₹200 − ₹75 = ₹125
The working, written in columns.
Cost –
₹125
Paid –
₹200
Balance –
₹75
The same card with the missing number filled in.
Q7Help Udaya Didi find the missing number(s) on this bill card.
Cost –
₹580
Paid –
__________
Balance –
₹120
The card as it is printed on page 98.
Answer
The customer paid ₹700.
Paid = Cost + Balance = ₹580 + ₹120 = ₹700
The working, written in columns.
Cost –
₹580
Paid –
₹700
Balance –
₹120
The same card with the missing number filled in.
Q8Help Udaya Didi find the missing number(s) on this bill card.
Cost –
__________
Paid –
__________
Balance –
__________
The card as it is printed on page 98.
Answer
This card is fully empty, so you make up your own bill. Only one rule must hold:
Cost + Balance = Paid
Cost –
₹245
Paid –
₹300
Balance –
₹55
One correct way to fill the card.
₹245 + ₹55 = ₹300
Q9Lou and Daisy buy 3 kg bananas to eat on the way with their friends. Which of the following options can they use to buy the bananas?The five money choices (a) to (e) printed on page 98.
Answer
First find what 3 kg of bananas cost. Bananas are ₹55 for 1 kg.
₹55 + ₹55 + ₹55 = ₹165
The working, written in columns.
Now check each option.
Option
Money in it
Enough for ₹165?
(a)
₹200
Yes
(b)
₹100 + ₹50 + ₹10 = ₹160 and one coin
Only if the coin is ₹5 or more
(c)
₹100 + ₹10 = ₹110
No
(d)
20 notes of ₹10 = ₹200
Yes
(e)
₹50 + ₹50 + ₹50 + ₹10 = ₹160
No
So they can pay with (a) ₹200 or (d) ₹200. (b) also works if its coin is a ₹5 coin: ₹160 + ₹5 = ₹165.
A Strange Puzzle! — Page 99Four children and the orange seller
Q1Four naughty kids on a walk come across a fresh orange crop. They ask the farmer the price of one. The farmer says, “Each costs ₹21”.
Two oranges each they buy. The farmer gives them with a sigh. They all reach in to their jackets, To take out notes from their pockets.
Each one pays a different note, Krishna a ₹50 and Sudama a ₹100 Mala a ₹200 and Neela a ₹500.
What is the balance that they each got?
Answer
Every child buys 2 oranges, so every child spends the same amount.
Cost for one child = ₹21 + ₹21 = ₹42
The working, written in columns.
Now take ₹42 away from the note each child gave.
Child
Paid
Working
Balance
Krishna
₹50
50 − 42
₹8
Sudama
₹100
100 − 42
₹58
Mala
₹200
200 − 42
₹158
Neela
₹500
500 − 42
₹458
Sudama’s balance, worked in columns.Neela’s balance, worked in columns.
Let Us Play — Page 100The triangle puzzle
Q1Place the numbers 1–6 in the blanks in such a way that the sum on each side of the triangle is 9. No numbers should be repeated.The triangle as it is printed, with 5 and 6 already placed and the tiles 1, 2, 3, 4 to be filled in.
Answer
Put 3 at the top, 4 on the left side, 2 at the bottom-left corner and 1 at the bottom-right corner.
Q4Can you make 12 on each side? Can you make 13?The second triangle, printed with all six circles empty.
Answer
Yes for 12. No for 13.
For 12, put 4, 5 and 6 at the corners and 1, 2 and 3 in the middles.
4 + 3 + 5 = 12 5 + 1 + 6 = 12 6 + 2 + 4 = 12
Each side adds to 12.
Q5What strategy did you use to place the numbers?The second triangle, printed with all six circles empty.
Answer
Strategy: Each corner number is added on two sides, so we choose the corners first. Small numbers (1, 2, 3) in the corners give a small side sum; big numbers (4, 5, 6) give a big side sum. Then each middle circle gets the number that completes its side.
In-text Questions — Page 101Add Up
Q1Estimate the number of teachers going. ____
Answer
About 50 teachers.
24 teachers → about 20 28 teachers → about 30 20 + 30 = about 50
Q224 teachers and 438 children are going from their school. 476 children from a neighbourhood school along with 28 teachers are also going to the same village. How many teachers are accompanying the children?
Answer
52 teachers are going with the children.
Teachers = 24 + 28
The working, written in columns.
2 T + 4 O 2 T + 8 O = 4 T + 12 O 10 ones make 1 ten, so 12 O = 1 T + 2 O = 5 T + 2 O = 52
In-text Questions — Page 102Add Up
Q1Estimate the number of children going on the trip. ____
Answer
About 900 children.
438 → about 400 476 → about 500 400 + 500 = about 900
Q2How many children are going on the trip? 438 + 476
Answer
914 children are going to Mawlynnong.
The working, written in columns.
4 H + 3 T + 8 O 4 H + 7 T + 6 O = 8 H + 10 T + 14 O 14 O = 1 T + 4 O, so the tens become 11 T 10 T = 1 H, so 11 T = 1 H + 1 T = 9 H + 1 T + 4 O = 914
In-text Questions — Page 103Add Up — buying pusaw
Q1Estimate the money they spent. __________
Answer
About ₹60.
₹38 → about ₹40 ₹16 → about ₹20 ₹40 + ₹20 = about ₹60
Q2Daisy and Lou ate one large piece of pusaw for ₹38. They liked it a lot and bought another small piece for ₹16. How much did they spend on pusaw? 38 + 16 = ____ T + ____ O. They spent ₹______The empty T and O boxes printed beside the sum on page 103.
Answer
They spent ₹54.
3 T + 8 O 1 T + 6 O = 4 T + 14 O 14 O = 1 T + 4 O = 5 T + 4 O = 54
The same boxes, filled in.
In-text Questions — Page 104Add Up — the piggy bank
Q1Estimate the money they took for the trip. ________
Answer
About ₹300.
₹185 → about ₹200 ₹125 → about ₹100 ₹200 + ₹100 = about ₹300
Q2Daisy and Lou had collected ₹185 in their piggy bank. Their mother gave them ₹125 more for the trip. How much money did they take for the trip? 185 + 125 = ____ H + ____ T + ____ O = ____ H + ____ T + ____ O. Daisy and Lou took ₹______ for the trip.The empty H, T and O boxes printed beside the sum on page 104.
Answer
They took ₹310 for the trip.
1 H + 8 T + 5 O 1 H + 2 T + 5 O = 2 H + 10 T + 10 O 10 O = 1 T, so the tens become 11 T 10 T = 1 H, so 11 T = 1 H + 1 T = 3 H + 1 T + 0 O = 310
The same boxes, filled in.
Let Us Do — Page 105Kalakshitij, column sums and Preeti’s school
Q11. In Kalakshitij, a school of performing arts, the following number of students are learning to sing and play the tabla. Estimate and then find the total number of students.
Tabla players
Singers
Total
Boys
78
532
_______ boys
Girls
95
346
_______ girls
Total
_______ tabla players
_______ singers
The Kalakshitij table as it is printed on page 105.
Answer
Estimate first: about 80 + 530 = 610 boys, about 100 + 350 = 450 girls, so about 1050 students in all.
Q215 more girls join the music school and they want to learn to play the tabla. How many girls play the tabla now?
Tabla players
Singers
Total
Boys
78
532
_______ boys
Girls
95
346
_______ girls
Total
_______ tabla players
_______ singers
The Kalakshitij table as it is printed on page 105.
Answer
110 girls play the tabla now.
Girls playing the tabla = 95 New girls = 15 95 + 15 = 110
The working, written in columns.
Q32. Add by aligning the numbers in columns in your notebook. a) 32 + 47
Answer
32 + 47 = 79
The working, written in columns.
Q4(b) 654 + 95
Answer
654 + 95 = 749
The working, written in columns.
Q5(c) 286 + 123
Answer
286 + 123 = 409
The working, written in columns.
Q6b) 476 + 324
Answer
476 + 324 = 800
The working, written in columns.
Q7(e) 700 + 289
Answer
700 + 289 = 989
The working, written in columns.
Q8(f) 534 + 483
Answer
534 + 483 = 1017
The working, written in columns.
Q93. Preeti’s school has 423 children. Her school has 178 children less than her cousin’s school. How many children study in Preeti’s cousin’s school?
Answer
601 children study in her cousin’s school.
Preeti’s school = 423 It has 178 less than the cousin’s school. So the cousin’s school = 423 + 178 = 601
The working, written in columns.
In-text Questions — Page 106Subtract It
Q1Estimate the difference ____
Answer
About 30 children.
83 → about 80 46 → about 50 80 − 50 = about 30
Q283 children bought Pusaw. 46 children bought fruit plates. How many more children bought Pusaw?
Answer
37 more children bought pusaw than fruit plates.
Difference = 83 − 46
The working, written in columns.
Q3Estimate the number of children who are waiting. ________
Answer
About 220 children.
438 → about 440 215 → about 220 440 − 220 = about 220
Q4All 438 decide to visit the famous Living Roots Bridge in Mawlynnong village. First, 215 children go to see the Living Roots Bridge. How many children are waiting to visit the Living Roots Bridge?
Answer
223 children are waiting.
Children waiting = 438 − 215
The working, written in columns.
8 − 5 = 3 ones 3 − 1 = 2 tens 4 − 2 = 2 hundreds = 2 H + 2 T + 3 O = 223
In-text Questions — Page 107Subtract It — money spent
Q1Estimate the answer. _________
Answer
About ₹130.
₹310 stays ₹310 ₹179 → about ₹180 ₹310 − ₹180 = about ₹130
Q2Lou and Daisy brought ₹310 in all. After spending on food and some gifts, they are left with ₹179. How much money have they spent till now?
Answer
They have spent ₹131.
Rupees spent = 310 − 179
The working, written in columns.
Let Us Solve — Page 108Ram Chacha’s mangoes and Ranganna’s dolls
Q1Estimate the answer. _________ (Ram Chacha’s mangoes)
Answer
About 270 mangoes.
527 → about 530 264 → about 260 530 − 260 = about 270
Q2Ram Chacha got 264 mangoes from his mango tree last year. This year he got 527 mangoes. How many more mangoes did he get this year?
Answer
He got 263 more mangoes this year.
More mangoes = 527 − 264
The working, written in columns.
Q3Estimate the answer. _________ (Ranganna’s dolls)
Answer
About 110 dolls.
639 → about 640 531 → about 530 640 − 530 = about 110
Q44. During the festival of dolls (Gombe Habba in Dussehra), Ranganna made 639 dolls. He was able to sell 531 dolls. How many dolls are left with him? No. of dolls left = _____________________
Let Us Solve — Page 109Question 5 — subtract by aligning the numbers in columns
Q15. Subtract by aligning the numbers in columns in your notebook. a) 83 – 29
Answer
83 − 29 = 54
The working, written in columns.
Q2b) 345 – 123
Answer
345 − 123 = 222
The working, written in columns.
Q3c) 763 – 437
Answer
763 − 437 = 326
The working, written in columns.
Q4d) 803 – 350
Answer
803 − 350 = 453
The working, written in columns.
Q5e) 900 – 328
Answer
900 − 328 = 572
The working, written in columns.
Let Us Solve — Pages 109 to 110Question 1 — the Wakanda village library
Q1a) Rami read Panchatantra Tales during the summer vacation. Kesu read Akbar Birbal, Karadi Tales and Blue Umbrella. Who do you think read more? How many more pages?
Kesu’s pages: 126 + 90.How many more Rami read: 236 − 216.
Q2b) Sumi has read 23 pages of Adventures of Feluda. How many more pages are left to complete the book?
Name of the book
Pages in the book
Swami and Friends
179
Panchantantra Tales
236
Karadi Tales
30
Akbar Birbal
96
Blue Umbrella
90
Adventures of Feluda
128
The Wakanda village library list, page 109.
Answer
105 pages are left.
Adventures of Feluda = 128 pages Read so far = 23 pages 128 − 23 = 105
The working, written in columns.
Q3c) Jaggu decides to read all the books listed here during his vacation. He has finished reading Swami and Friends, Akbar Birbal and 50 pages of Feluda in 4 weeks. How many more pages does he have to read to finish reading all the books?
Let Us Solve — Pages 110 to 111Question 2 — the daily train between Delhi and Aligarh
Q1A daily train between Delhi and Aligarh travels a distance of 131 km. Look at the picture below and answer the questions that follow. a) How many passengers are there on the train when it leaves Dadri?The train picture on page 110, with the four stations in order.
Answer
1021 passengers are on the train when it leaves Dadri.
At New Delhi: 894 boarded → 894 At Ghaziabad: 894 + 158 = 1052, then 1052 − 23 = 1029 At Dadri: 1029 + 67 = 1096, then 1096 − 75 = 1021
894 + 158 at Ghaziabad.1052 − 23 at Ghaziabad.1029 + 67 at Dadri.1096 − 75 at Dadri.
Q2b) Find the number of people who got off the train at Aligarh.The train picture on page 110, with the four stations in order.
Answer
1021 people got off at Aligarh.
Aligarh Jn. is the last station of this train. So everybody still on the train must get off there. People on the train after Dadri = 1021 People who got off at Aligarh = 1021
Q3c) Were there more people on the train in New Delhi or in Aligarh? How much more/less?The train picture on page 110, with the four stations in order.
Answer
There were more people in Aligarh — 127 more.
In New Delhi = 894 In Aligarh = 1021 1021 − 894 = 127
The working, written in columns.
Q4d) How many people travelled altogether by the train?The train picture on page 110, with the four stations in order.
Answer
1119 people travelled by the train altogether.
Boarded at New Delhi = 894 Boarded at Ghaziabad = 158 Boarded at Dadri = 67 894 + 158 = 1052 1052 + 67 = 1119
1052 + 67.
Let Us Solve — Page 111Column frames, quick ways and notebook practice
Q1a. Solve in the H T O frame.Question a. as it is printed on page 111.
Answer
452 + 89 = 541
The working, written in columns.
Q2b. Solve in the H T O frame.Question b. as it is printed on page 111.
Answer
641 − 273 = 368
The working, written in columns.
Q3c. Find quick ways of solving. Think about some of the strategies you learnt in Grade 3. 326 + 25 = _______
Answer
326 + 25 = 351
326 + 25 = 326 + 20 + 5 = 346 + 5 = 351
Q4675 + 5 = _______
Answer
675 + 5 = 680
675 + 5 5 ones and 5 ones make 10 ones = 1 ten 7 tens + 1 ten = 8 tens = 680
Q5410 – 12 = _______
Answer
410 – 12 = 398
410 − 12 = 410 − 10 − 2 = 400 − 2 = 398
Q6204 – 10 = _______
Answer
204 – 10 = 194
204 − 10 Only the tens change: 0 tens cannot give 1 ten, so 2 hundreds become 1 hundred and 10 tens = 194
Q7811 + 99 = _______
Answer
811 + 99 = 910
811 + 99 = 811 + 100 − 1 = 911 − 1 = 910
Q8945 – 19 = _______
Answer
945 – 19 = 926
945 − 19 = 945 − 20 + 1 = 925 + 1 = 926
Q9d. Solve by aligning the numbers in columns in your notebook. 1. 38 + 943
Answer
38 + 943 = 981
The working, written in columns.
Q102. 465 + 305
Answer
465 + 305 = 770
The working, written in columns.
Q113. 435 + 462
Answer
435 + 462 = 897
The working, written in columns.
Q124. 764 – 657
Answer
764 − 657 = 107
The working, written in columns.
Q135. 518 – 209
Answer
518 − 209 = 309
The working, written in columns.
Q146. 879 – 53
Answer
879 − 53 = 826
The working, written in columns.
Let Us Solve — Page 112Question e — make your own numbers and word problems
Q1e. Find two numbers such that their sum is 856. Find another two numbers such that their difference is 563. Make your own word problems with these numbers.
Answer
Many answers are correct. Here is one pair for each box.
856 = 400 + 456 563 = 900 − 337
Sample word problems:
A village planted 400 saplings last year and 456 saplings this year. How many saplings in all? 856 saplings.
A library has 900 books. Children borrowed 337 of them. How many books are left on the shelves? 563 books.
Number Pair Hunt — Pages 112 to 113The grid of numbers
Q1How many number pairs are there in this grid?
35
100
179
68
111
185
143
54
300
48
225
190
54
321
63
167
The number grid printed on page 112.
Answer
There are 24 number pairs.
Side by side (across): 4 rows × 3 pairs = 12 One above the other (down): 4 columns × 3 pairs = 12 12 + 12 = 24
Q2Should we check every number pair to find out which is the largest sum or difference?
35
100
179
68
111
185
143
54
300
48
225
190
54
321
63
167
The number grid printed on page 112.
Answer
No. We need not check all 24 pairs. For the largest sum we look only at pairs of big numbers (like 225 and 190). For the largest difference we look for a big number next to a small one (like 321 and 48).
Q31. Find the number pair whose sum is the greatest.
35
100
179
68
111
185
143
54
300
48
225
190
54
321
63
167
The number grid printed on page 112.
Answer
The pair is 225 and 190. Their sum is 415.
The working, written in columns.
Q42. Find the number pair whose sum is the smallest.
35
100
179
68
111
185
143
54
300
48
225
190
54
321
63
167
The number grid printed on page 112.
Answer
The pair is 68 and 54. Their sum is 122.
The working, written in columns.
Q53. Find the number pair whose difference is the greatest.
35
100
179
68
111
185
143
54
300
48
225
190
54
321
63
167
The number grid printed on page 112.
Answer
The pair is 321 and 48. Their difference is 273.
The working, written in columns.
Q64. Find the number pair whose difference is the smallest.
35
100
179
68
111
185
143
54
300
48
225
190
54
321
63
167
The number grid printed on page 112.
Answer
The pair is 68 and 54. Their difference is 14.
The working, written in columns.
The Missing Digits — Page 113Fill the missing digits
Q1Fill the missing digits below to make each of the following sums correct. Puzzle 1: __ 6 + 1 __ = 5 0The puzzle as it is printed on page 113.
Answer
The sum is 36 + 14 = 50.
Ones: 6 + ? must end in 0 → 6 + 4 = 10 Write 0 and carry 1 ten. Tens: ? + 1 + 1 = 5 → ? = 3
The same puzzle with the missing digits filled in.
Q2Puzzle 2: 1 __ + 2 __ = 3 8The puzzle as it is printed on page 113.
Answer
The two ones digits must add up to 8. One correct answer is 15 + 23 = 38.
Tens: 1 + 2 = 3, and the answer has 3 tens, so nothing is carried from the ones. Ones: ? + ? = 8
The same puzzle with the missing digits filled in.
Q3Puzzle 3: 3 __ 2 + __ 8 8 = 8 9 0The puzzle as it is printed on page 113.
The same puzzle with the missing digits filled in.
Q4Puzzle 4: 7 __ − 4 __ = 2 7The puzzle as it is printed on page 113.
Answer
One correct answer is 70 − 43 = 27.
Tens: 7 − 4 = 3, but the answer shows only 2 tens. So one ten went to the ones → regrouping happened. Ones: 10 + ? − ? = 7, so the lower digit is 3 more than the upper one.
The same puzzle with the missing digits filled in.
Q5Puzzle 5: 6 5 − __ __ = 2 5The puzzle as it is printed on page 113.
Answer
The number to be taken away is 40. So 65 − 40 = 25.
The number taken away = 65 − 25 = 40 Ones: 5 − 0 = 5 Tens: 6 − 4 = 2
The same puzzle with the missing digits filled in.
Q6Puzzle 6: 4 7 __ − 1 4 __ = __ 2 7The puzzle as it is printed on page 113.
Answer
One correct answer is 470 − 143 = 327.
Tens: 7 − 4 = 3, but the answer shows 2 tens, so one ten was given to the ones. Ones: 10 + ? − ? = 7 → the lower digit is 3 more than the upper one. Hundreds: 4 − 1 = 3
The same puzzle with the missing digits filled in.