Finding a 20% tip no calculator We have 2 methods to calculate a 20% tip. Divide by 5 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