Finding 2 1/2 percent of a number

1. Choose a number (start with 2 digits and advance to 3 with practice).
2. Divide by 4 (or divide twice by 2).
3. Move the decimal point one place to the left.

   Example:

1. If the number selected is 86:
2. Divide 86 by 4: 86/4 = 21.5
3. Move the decimal point one place to the left.: 2.15
4. So 2 1/2% of 86 = 2.15.

   See the pattern?

1. If the number selected is 648:
2. Divide 648 by 2 twice: 648/2 = 324, 324/2 = 162
3. Move the decimal point one place to the left.: 16.2
4. So 2 1/2% of 648 = 16.2.

Practice dividing by 4, or by 2 twice, and you will be able to find these answers faster than with a calculator.