elementary-math Module
Interactive Simulation Screen
SYS_OKLesson Directive // Decimals & PercentagesREF_CORE
Fractions to Decimals
Hover over a variable in the formula above, or see glossary below:
The Number
Fractions are just division. To convert a fraction like 3/4 to a decimal, divide the top number by the bottom number (3 ÷ 4 = 0.75).
INSIGHT: The fraction bar literally means "divided by".
Decimals to Percentages
Percent means "per 100". To convert a decimal to a percentage, multiply it by 100 (which shifts the decimal point two places to the right) and add a % sign. 0.75 becomes 75%.
INSIGHT: Decimals and percentages are two ways of writing the same exact value.
Finding the Percent of a Number
To find a percentage of a number, first convert the percentage to a decimal, then multiply. For example, to find 20% of 50: convert 20% to 0.20, then multiply 0.20 × 50 = 10.
INSIGHT: The word "of" in math often means "multiply".