Theory
How do you calculate a fraction of a number?
A fraction of a number means that you take part of the whole.
The denominator tells you into how many equal parts you divide the whole. The numerator tells you how many of those parts you need.
That is why you first divide by the denominator and then multiply by the numerator.
- Divide by the denominatorThe denominator tells you into how many equal parts you divide the whole.
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 numeratorMultiply the value of one part by the numerator, because the numerator tells you how many of those parts you take.
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
34 of 28.
- Divide by the denominator28 ÷ 4 = 7.
- Multiply by the numerator7 × 3 = 21.