Home › Class 4th › Maths › Math-Mela › The Cleanest Village › NCERT Solutions for Class 4th Maths Chapter 7 Kalakshitij, column sums and Preeti’s school — Let Us Do NCERT Solutions for Class 4th Maths Chapter 7 Kalakshitij, column sums and Preeti’s school — Let Us Do Book page 105 Updated on2026-09-19
Q1. 1. 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.
Answer The Kalakshitij table as it is printed on page 105. Estimate first: about 80 + 530 = 610 boys, about 100 + 350 = 450 girls, so about 1050 students in all.
Now the exact numbers.
Boys = 78 + 532 = 610 441 173 878 1051
H T O 1 1 7 8 5 3 2 + 6 1 0 Boys: 78 + 532. H T O 1 1 9 5 3 4 6 + 4 4 1 Girls: 95 + 346. H T O 1 1 7 8 9 5 + 1 7 3 Tabla players: 78 + 95. H T O 5 3 2 3 4 6 + 8 7 8 Singers: 532 + 346. The same table with every box filled in. Why it happens: The last box can be found two ways — 610 + 441 and 173 + 878 — and both give 1051, because both count the same children.
Check it yourself: 173 + 878 = 1051. The row totals and the column totals must agree.
Q2. 15 more girls join the music school and they want to learn to play the tabla. How many girls play the tabla now?
Answer The Kalakshitij table as it is printed on page 105. 110 girls play the tabla now.
Girls playing the tabla = 95110
H T O 1 1 9 5 1 5 + 1 1 0 The working, written in columns. Why it happens: 5 ones and 5 ones make 10 ones. Those ten ones become 1 ten, so the ones place gets a 0.
Q3. 2. Add by aligning the numbers in columns in your notebook. a) 32 + 47
Answer 32 + 47 = 79
T O 3 2 4 7 + 7 9 The working, written in columns. Why it happens: No column reaches ten, so nothing has to be regrouped here.
Answer 654 + 95 = 749
H T O 1 6 5 4 9 5 + 7 4 9 The working, written in columns. Tip: 95 has no hundreds. Write it under 654 so that 5 sits below 4 and 9 sits below 5.
Answer 286 + 123 = 409
H T O 1 2 8 6 1 2 3 + 4 0 9 The working, written in columns. Why it happens: 6 ones and 3 ones make 9 ones, but 8 tens and 2 tens make 10 tens, which is 1 hundred.
Tip: The Hindi edition prints this sum as 86 + 123 , and 86 + 123 = 209 . Use the numbers printed in your own book.
Answer 476 + 324 = 800
H T O 1 1 4 7 6 3 2 4 + 8 0 0 The working, written in columns. Why it happens: Both the ones and the tens fill up to ten, so we regroup twice and the answer ends in 00.
Tip: The English book prints this item as b) by mistake. It should be d) .
Answer 700 + 289 = 989
H T O 7 0 0 2 8 9 + 9 8 9 The working, written in columns. Why it happens: 700 has 0 tens and 0 ones, so the tens and ones of the answer are simply those of 289.
Answer 534 + 483 = 1017
Th H T O 1 1 5 3 4 4 8 3 + 1 0 1 7 The working, written in columns. Why it happens: 5 hundreds and 4 hundreds and the carried hundred make 10 hundreds, and 10 hundreds are 1 thousand.
Tip: The Hindi edition prints this sum as 34 + 483 , and 34 + 483 = 517 . Use the numbers printed in your own book.
Q9. 3. 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 = 423less than the cousin’s school.601
H T O 1 1 4 2 3 1 7 8 + 6 0 1 The working, written in columns. Why it happens: Preeti’s school is the smaller one. To go back to the bigger school we must put the 178 children back, so we add.
Check it yourself: 601 − 178 = 423, which is Preeti’s school again.
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