Finding a 20% tip no calculator

Finding a 20% tip no calculator

We have 2 methods to calculate a 20% tip.

1. Divide by 5
2. Shift one decimal place left and take the value. Multiply by 2

Example: 180 tip, find a 20% tip:

Method 1:
180/5 = 36

Method 2:
Move decimal place left = 18
Multiply this value by 2: 18 * 2 = 36