Percent simply means "per 100," so any percentage number can be expressed as number/100. For example, 75 percent can be expressed as the fraction 75/100 or as the decimal fraction 0.75.
To convert a fraction or decimal to a percentage, simply multiply by 100. For example, the fraction 1/4 equals the decimal fraction 0.25. To convert this to a percentage, multiply 0.25 by 100 to get 25 percent. When a person multiplies by 100, he moves the decimal point over two places.
To convert a percentage back to a fraction, simply reverse the procedure and divide by 100. The percentage 85 percent can be converted back into a fraction by dividing by 100 and moving the decimal point over two places to the left to get 0.85. This can also be expressed as 85/100.
For an example of calculating percentages, consider that 16 people out of 64 are male. To find out what percentage of the total sample is male, first divide 16 by 64 to get the decimal fraction 0.25. Then, multiply 0.25 by 100 to get the percentage 25 percent. Twenty-five percent of the people in the sample are male.
Other percentage problems are solved in a similar manner. Just remember, all percentage problems use some form of the basic percentage formula, which is part/whole = percent/100.