Theory
How do you calculate the whole from a percentage?
The whole is 100%. Sometimes you know how much a smaller percentage is worth.
First work back to 1% by dividing the given value by the percentage.
Then multiply by 100 to find the whole amount or number.
- Work back to 1%Divide the part by the percentage to work back to 1%.
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.
- Work forward to 100%Multiply the value of 1% by 100 to find 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.
25% is 18. What is 100%?
- Work back to 1%18 ÷ 25 = 0,72.
- Work forward to 100%0,72 × 100 = 72.