AMO 2017 – Secondary 1 (Grade 7) Question 25

A cricket can climb a staircase by leaping either $1$ step or $2$ steps with each bound. In how many different ways can it climb a $7$-step staircase? For example, a $3$-step staircase has exactly three ways: $1+1+1$, $1+2$ and $2+1$.