Fibonacci Series

Question

Fibonacci Series
0 1 1 2 3 5 8 13 .......
sum of previous 2 numbers gives next number.
0+1=1
1+1=2
1+2=3
2+3=5

https://code.sololearn.com/cLEDZz5KCNA3/?ref=app

Answer 1

https://code.sololearn.com/cLEDZz5KCNA3/?ref=app

Answer 2

https://code.sololearn.com/cg8P3QBlO4IB/?ref=app

Answer 3

https://code.sololearn.com/c668XW75FAW2/?ref=app