Question

Which number should come next in the series? 1 - 1 - 2 - 3 - 5 - 8 – 13

Answer 1

21
The series would be adding the previous number--
1+1=2
1+2=3
2+3=5
3+5=8
5+8=13
8+13= 21
and so on

Answer 2

The number which should come next is 21.

8+13 is 21