Content

• To step
• Method 1 of 3: Percent
• Method 2 of 3: Decimal Fractions
• Method 3 of 3: Fractions
• Tips
• Warnings
• Necessities

Do you need help with your homework or are you studying for a test? Here you can learn how to convert fractions, percentages and decimal numbers so that you will pass every test with flying colors!

To step

Method 1 of 3: Percent

1. Convert a percent to a decimal fraction. To do this, move the comma two places to the left. If the percentage has no decimal places, pretend it has a zero. So 75 becomes 75.0. Then move the comma as indicated above.
   • Examples:
     • 75% becomes 0.75
     • 40% becomes 0.40
     • 3.1% becomes 0.031
2. Turn a percentage into a fraction. The percentage becomes the numerator, which you then divide by 100 and then simplify.
   • Example: 36% becomes 36/100.
   • Simplify this by finding the largest number that you can divide by both 100 and 36. In this case it is 4.
   • Find the number of times that 4 goes into 36 and 100. Simplified, the fraction becomes 9/25.

Method 2 of 3: Decimal Fractions

1. Converting a decimal fraction to a percentage. Move the comma two places to the right.
   • Examples:
     • 0.32 becomes 32%
     • 0.07 becomes 7%
     • 1.25 becomes 1.25%
     • 0.083 becomes 8.3%
2. Turn a decimal number into a fraction. Move the comma two places to the right. This will now be the numerator, which you then divide by 100.
   • Examples:
     • 0.32 becomes 32/100
     • 0.08 becomes 8/100
   • Then simplify the fraction as far as possible. For example: 75/100 can be reduced to 3/4.
3. Convert a repeating decimal number to a fraction. Determine how many repeating decimal places there are. For example: if the decimal number is 0.131313 ... then there are 2 repeating decimal places (the number 13).
   • Multiply the number by 10 to the power of n, where n is the number of repeating decimal places. For example, 0.131313 ... is then multiplied by 100 (10) and then we get 13.131313 ... as the answer.
   • To find the denominator, subtract the number you started with from the number you just calculated. So, 13.131313 ... - 0.131313 ... = 13. So the numerator is 13.
   • To find the denominator, subtract 1 from the number by which you multiplied the original number. For example, 0.131313 ... was multiplied by 100, so the denominator becomes 100 - 1 = 99.
   • Examples
     • 0.333 ... becomes 3/9
     • 0.111 ... becomes 1/9
     • 0.142857142857 ... becomes 142857/999999
     • If necessary, try to simplify the fraction as much as possible. For example, 142857/999999 becomes 1/7.

Method 3 of 3: Fractions

1. Changing a fraction to a decimal number. Remember that 5/17 is the same as 5 divided by 17.
   • Determine how many digits you want after the decimal point. If you want three numbers, write the 5 as 5,000. If you want two decimal places, write 5.00
   • Divide your number by 17.5 / 17 can be written as a decimal point with 3 decimal places to get 0.294. Written with two decimal places, this becomes 0.29
2. Changing a fraction to a percentage. Divide the numerator by the denominator, multiply by 100 and add a percent sign.
   • If you have 4/8 as a fraction, 4: 8 equals 0.50. Multiplied by 100 it becomes 50. With a percent sign, it looks like 50%
   • Examples
     • 3/10 = 30%
     • 5/8= 62,5%

Tips

• Know the multiplication tables.
• Don't use a calculator if you don't intend to.
• Many calculators have a special function for fractions. You may be able to simplify a fraction with your calculator, so check your manual to see if this is possible.

Warnings

• Make sure the decimal point (comma) is in the right place.
• Divide the numerator by the denominator when converting a fraction to a decimal.
• Dividing is the same as multiplying by the opposite, so if you divide two fractions together, then reverse the second fraction and multiply it by the first.

Necessities

• Paper and pencil
• An ordinary calculator