| Operation | Explanation | Example |
|---|---|---|
Convert a decimal to a percent |
Move the decimal point 2 places to the right and add a percent (%) sign. If you need to, add a zero on the back to get the second decimal place. | .123 = 12.3% |
Convert a percent to a decimal |
Move the decimal point 2 places to the left. If you need to, put a zero on the front. | 5% = .05 |
Convert a fraction to a decimal |
Divide the numerator by the denominator, using your calculator. | 1/8 = .125 |
| Convert a percent to a fraction |
First turn the number into a decimal. Then turn the number into a fraction by putting it over 10, 100, 1000, or whatever number is big enough to have enough zeroes for each place after the decimal. |
18% = .18 = 18/100 = 9/50 |
Memorize the common fractions, decimals and percents in this table | ||||||
|---|---|---|---|---|---|---|
| Fraction | Decimal | Percent | Fraction | Decimal | Percent | |
 | .25 | 25% |  | .125 |  |
|
 | .5 | 50% |  | .25 | 25% | |
 | .75 | 75% |  | .375 | 37.5% | |
 | .5 | 50% | ||||
 | .33333 |  |
 | .625 | 62.5% | |
 | .66666 |  |
 | .75 | 75% | |
 | .875 | 87.5% | ||||
 | .1 | 10% | ||||
 | .2 | 20% |  | 1.0 | 100% | |
 | .3 | 30% |  | 2.0 | 200% | |