Theory
How do you calculate a percentage of a number?
A percentage is a part of 100.
First convert the percentage to a decimal number by dividing by 100.
Multiply that decimal number by the whole whose percentage you want to find.
- Divide the percentage by 100Divide the percentage by 100 to write it as a decimal number.
Dividing means sharing an amount fairly or seeing how many equal groups fit into it.
The first number is the total amount. The second number tells you what you divide by.
Always check whether the division works out exactly. If it does not, you get a decimal number or fraction as the answer.
- Multiply by the wholeMultiply this decimal number by the whole.
You use multiplication with equal groups.
A × B means that you take the same amount B, A times.Instead of adding again and again, you calculate the product all at once.
Calculate 25% of 80.
- Divide the percentage by 10025 ÷ 100 = 0,25.
- Multiply by the whole80 × 0,25 = 20.