Question 1

We will find the multiples for each pair of numbers up to 60. Then we will identify their common multiples.

Step 1 — Playing with 2 and 5

First, we list multiples of 2 up to 60. These are the 'idli' numbers. $2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60$

Next, we list multiples of 5 up to 60. These are the 'vada' numbers. $5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60$

Now, we find numbers in both lists. These are the common multiples, or 'idli-vada'. $10, 20, 30, 40, 50, 60$

$\boxed{\text{Common multiples of 2 and 5: } 10, 20, 30, 40, 50, 60}$

Step 2 — Playing with 3 and 7

First, we list multiples of 3 up to 60. These are the 'idli' numbers. $3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60$

Next, we list multiples of 7 up to 60. These are the 'vada' numbers. $7, 14, 21, 28, 35, 42, 49, 56$

Now, we find numbers in both lists. These are the common multiples, or 'idli-vada'. $21, 42$

$\boxed{\text{Common multiples of 3 and 7: } 21, 42}$

Step 3 — Playing with 4 and 6

First, we list multiples of 4 up to 60. These are the 'idli' numbers. $4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60$

Next, we list multiples of 6 up to 60. These are the 'vada' numbers. $6, 12, 18, 24, 30, 36, 42, 48, 54, 60$

Now, we find numbers in both lists. These are the common multiples, or 'idli-vada'. $12, 24, 36, 48, 60$

$\boxed{\text{Common multiples of 4 and 6: } 12, 24, 36, 48, 60}$

Answer

(a) Common multiples of 2 and 5 are: 10, 20, 30, 40, 50, 60. (b) Common multiples of 3 and 7 are: 21, 42. (c) Common multiples of 4 and 6 are: 12, 24, 36, 48, 60.