Question

Look at these growing patterns. Find out what to add to each number to get the next one:

1, 3, 7, 13, ______, ______, ______, ______, ______. 

Answer 1

First number: 1

Second number: 3 (i.e. 1 + 2)

Third number: 7 (i.e. 3 + 4)

Fourth number: 13 (i.e. 7 + 6)

Thus, next number will be

13 + 8 = 21

21 + 10 = 31

31 + 12 = 43

43 + 14 = 57

57 + 16 = 73

So, the final pattern will be: 1, 3, 7, 13, 21, 31, 43, 57, 73.