Question

What numbers are missing from the pattern below?

15,16,18,21,?,?,?,?, 51,60,70,81

Answer 1

15, 16, 18, 21, 25, 30, 36, 43, 51, 60, 70, 81

Explanation:

It added +1 each time. So 15, 16 was normal then it added 1 onto 1 then 1 onto 2 and so fourth.