NCERT Solutions for Class 6th Maths Chapter 5 Playing with other number pairs — In-text Questions
Book page 108 & 109 Updated on2026-09-19
Q1.
Let us now play the ‘idli-vada’ game with different pairs of numbers: a. 2 and 5, b. 3 and 7, c. 4 and 6. We will say ‘idli’ for multiples of the smaller number, ‘vada’ for multiples of the larger number and ‘idli-vada’ for common multiples. Draw a figure similar to Fig. 5.1 if the game is played up to 60.
Fig. 5.1 (page 108) — the numbers up to 30 sorted into “multiples of 3”, “multiples of 5” and the overlap.
Answer
For each pair, first find the first common multiple. Then every next common multiple is obtained by adding that number again.
Pair
‘idli’ (smaller number)
‘vada’ (larger number)
‘idli-vada’ up to 60
a. 2 and 5
multiples of 2
multiples of 5
10, 20, 30, 40, 50, 60
b. 3 and 7
multiples of 3
multiples of 7
21, 42
c. 4 and 6
multiples of 4
multiples of 6
12, 24, 36, 48, 60
Now the three figures. In each one, write the ‘idli’-only numbers in the left circle, the ‘vada’-only numbers in the right circle and the common multiples in the overlap.
c. 4 and 6 — first common multiple 12
‘idli’ only: 4, 8, 16, 20, 28, 32, 40, 44, 52, 56 (10 numbers)
‘vada’ only: 6, 18, 30, 42, 54 (5 numbers)
‘idli-vada’: 12, 24, 36, 48, 60 (5 numbers)
Something worth noticing: for 2 and 5 the first ‘idli-vada’ is 10 = 2 × 5, and for 3 and 7 it is 21 = 3 × 7 — the product itself. But for 4 and 6 it is only 12, which is less than 4 × 6 = 24. The reason is that 4 and 6 share the common factor 2. You will meet this idea again on page 116.
Q2.
Yesterday, we played this game with two numbers. We ended up saying just ‘idli’ or ‘idli-vada’ and nobody said just ‘vada’! One of the numbers was 4. Which of the following could be the other number: 2, 3, 5, 8, 10?
Answer
Answer: 8.
Nobody said just ‘vada’. That means every multiple of the other number was also a multiple of 4 — so it always turned into an ‘idli-vada’. This happens only when the other number is itself a multiple of 4.
Why: ‘vada’ is said at multiples of 8, and every multiple of 8 (8, 16, 24, …) is also a multiple of 4. So a plain ‘vada’ never gets a chance — it is always upgraded to ‘idli-vada’.