(a) Lets take ‘a’ be the missing number,

So, we have,

2 × a = 6

a = 6/2 = 3

a = 3

So,

2 × 3 = 6

And

5 × a = 10

a = 10/5 = 2

5 × 2 = 10

Missing numbers are 3 and 2.

(b) As we know 60 = 30 × 2

30 = 10 × 3

10 = 5 × 2

Missing numbers are, 2, 5, 3 and 2.