You can find 5 percent of any number in 4 seconds using this trick. So what is the trick?
Trick: Divide the number by 2 and move the decimal point one place to the left. The process just involves two easy steps as shown in the following examples.
Example #1: 5% of 36
Step 1: Divide 36 by 2.
36/2 = 18 = 18.0
Step 2: Move the decimal point one place to the left.
1.8
5% of 36 = 1.8
Example #2: 5% of 180
Step 1: Divide 180 by 2.
180/2 = 90 = 90.0
Step 2: Move the decimal point one place to the left.
9.00
5% of 180 = 9
Example #3: 5% of 13
Step 1: Divide 13 by 2.
13/2 = 6.5
Step 2: Move the decimal point one place to the left.
0.65
5% of 13 = 0.65
Example #4: 5% of 650
Step 1: Divide 650 by 2.
650/2 = 325 = 325.0
Step 2: Move the decimal point one place to the left.
32.50
5% of 650 = 32.5