# Three button calculator

A calculator has only 3 buttons. The first multiplies the current value by 3, the second adds 2 and the third subtracts 2. Starting with 0 what is the least number of presses you need to reach 100?

• Now another question could be: determine all non-negative integers $k$ such that you cannot go from $0$ to $100$ by pushing $k$ buttons. – WhatsUp Nov 12 '19 at 0:25