Fractions, decimals and percentages are all ways of expressing numbers. Each can be converted from one to another.
Below are some of the commonly used percentages, decimals and fractions.
20%

20/100 = 1/5 

40%


90%


Methods of Conversion
Fractions to Decimals
To convert a fraction into a decimal, divide the numerator by the denominator.
e.g. ^{3}⁄_{4} = 3 ÷ 4 = 0.75
2^{1}⁄_{2} = ^{5}⁄_{2} = 5 ÷ 2 = 2.5
Decimals to Fractions
To convert a decimal into a fraction, put the digits after the decimal point as the numerator, and put 10, 100, 1000 ... (depending on the number of decimal places) as the denominator. Then simplify the fraction whenever possible.
e.g.  0.75 = ^{75}⁄_{100} = ^{3}⁄_{4} 
0.4 = ^{4}⁄_{10} = ^{2}⁄_{5} 
Decimals to Percentages
To convert a decimal to a percentage, multiply the decimal by 100.
This is done by moving the decimal point two places to the right.
e.g. 0.25 = 0.25 × 100% = 25% 1.625 = 1.625 × 100% = 162.5%
Percentages to Decimals
To convert a percentage to a decimal, divide the percentage by 100 .
This is done by moving the decimal point two places to the left.
e.g. 35% = 35 ÷ 100 = 0.35 6% = 6 ÷ 100 = 0.06
Fractions to Percentages
To convert a fraction to a percentage, multipy the fraction by 100.e.g. ^{1}⁄_{4} = ^{1}⁄_{4} × 100% = 25%^{9}⁄_{8} = ^{9}⁄_{8} × 100% = 112.5%
Percentages to Fractions
To convert a percentage to a fraction, divide the percentage by 100.
This is done by changing the denominator to 100 and then simplifying, if possible.
e.g. 30% = ^{30}⁄_{100} = ^{3}_{10}150% = ^{150}⁄_{100} = ^{3}⁄_{2}
Try this activity to practice converting between decimals, fractions and percentages.