Turning percents into decimals
To turn a percentage into a decimal number, always:
- Drop the percent sign, and
- Move the decimal point two places to the LEFT.
For example:
- 1% is .01
- 2% is .02
- 3% is .03
- 9% is .09
- and 10% is .10 (same as .1)
- 25% is .25
- 33% is .33
- 99% is .99
- and 100% is 1.00 (same as 1)
Your calculator may put a zero in front of the decimal point. It doesn't matter, because ".01" and "0.01" are just two ways of writing the same number.
Why is .10 the same as .1? If a decimal number ends in a zero, you can always leave the zero off. So .1, .10, and .1000000 are all the same number: They all equal 10%. And .01, .010, and .0100000 are all the same: They all equal 1%. But .1 and .01 are very different: .1 is 10% and .01 is 1%.
What if the percentage has a decimal in it? Let's say you're offered 18.6% interest. It's already a decimal number, right? Wrong! It's still a percentage.
- Drop the percent sign, and
- Move the decimal point two places to the LEFT.
So the decimal number for 18.6% is .186
