NCERT Solutions for Class 4th Maths Chapter 3 Crayons Arrangement — Crayons Arrangement
Book page 37 Updated on2026-09-19
Q1.
Circle the odd numbers and put a square around each even number. Use the crayons arrangement, if needed.The eleven numbers printed on page 37. Two of them are already marked in the book.The crayon in the book, with the numbers 1 to 100 written two in a row.
Answer
The eleven numbers printed on page 37. Two of them are already marked in the book.
Look at the ones digit of each number and then mark it.
Every number marked: a ring for odd, a box for even.
Put a circle (odd)
5, 51, 37, 43, 69
Put a square (even)
8, 36, 22, 30, 38, 52
The book has already ringed 5 and boxed 8 for you. So you have to mark the other nine: 36, 69, 22, 51, 30, 38, 37, 52, 43.
The crayon strip helps. Find the number on the crayon: if it is in the left column it is odd, if it is in the right column it is even.
The crayon in the book, with the numbers 1 to 100 written two in a row.
Why it happens: Tens always pair off by themselves, so only the ones digit decides. 52 is 5 tens and 2 ones; the 2 ones make one pair, so nothing is left over.
Tip: You never need to count a big number in twos. Just cover the tens with your thumb and look at the last digit.
Q2.
Which numbers are even and which are odd? Discuss.The eleven numbers printed on page 37. Two of them are already marked in the book.
Answer
The eleven numbers printed on page 37. Two of them are already marked in the book.
Even numbers
8, 22, 30, 36, 38, 52
Odd numbers
5, 37, 43, 51, 69
Tell the class how you decided. This is the reason to give:
22, 30, 36, 38, 52 and 8 end in 2, 0, 6, 8, 2 and 8. Those digits are even, so the numbers are even.
37, 43, 51, 69 and 5 end in 7, 3, 1, 9 and 5. Those digits are odd, so the numbers are odd.
52 → 5 tens and 2 ones → the 2 ones make 1 pair → even 51 → 5 tens and 1 one → that 1 one has no partner → odd
Why it happens: Ten is 5 pairs, so every ten pairs off perfectly. Only the leftover ones can spoil the pairing.
Did you know? This is why a car number plate, a house number or a bus number can be called even or odd just by glancing at its last digit.
Q3.
Explore your textbook and find out what Shirley has seen. Draw a square on the even numbers. Put a circle on the odd numbers.
Answer
An open Maths book. The page number sits at the bottom of each page.
What Shirley has seen: in her Maths book every left-hand page has an even number and every right-hand page has an odd number.
Do this yourself:
Open this book at any place and keep it flat.
Read the page number at the bottom of the left page — for example 36. Put a square on it.
Read the page number on the right page — 37. Put a circle on it.
Turn the page and do it again: 38 on the left, 39 on the right.
Left pages: 34, 36, 38, 40 … → all even Right pages: 35, 37, 39, 41 … → all odd Reading straight through: 34, 35, 36, 37, 38 → even, odd, even, odd, even
Why it happens: Every sheet of paper has two sides. The front side is a right-hand page and the back side is the next left-hand page, so the numbers keep changing turn by turn.
Try This: Check a story book and a newspaper too. You will find the same rule in every printed book.