Maths · Fractions
What fractions are
Understand numerator, denominator, and equal parts of a whole.
What is a fraction?
A fraction is a part of a whole. Imagine a pizza cut into equal slices. Each slice is a fraction of the whole pizza. The pieces must be the same size to be fair. If you eat one slice out of four, you ate one-quarter of the pizza.
The numerator
The numerator is the top number in a fraction. It tells you how many parts you have. If you have 3 slices out of 8, the numerator is 3. The numerator counts the pieces you are talking about.
The denominator
The denominator is the bottom number in a fraction. It tells you how many equal parts make the whole. If a cake is cut into 6 pieces, the denominator is 6. The denominator shows the total number of parts.
Equal parts matter
For fractions to work, all parts must be equal in size. You cannot cut a chocolate bar into big and small pieces. Each piece must be exactly the same. Only then can we use fractions to describe them fairly.
Worked examples
1. A sandwich is cut into 4 equal pieces. You eat 1 piece. What fraction did you eat?
- The whole sandwich is cut into 4 equal parts.
- The denominator is 4 because there are 4 parts in total.
- You ate 1 part, so the numerator is 1.
- The fraction is 1/4.
2. A rectangle is divided into 5 equal strips. 3 strips are shaded. What fraction is shaded?
- The rectangle has 5 equal parts in total.
- The denominator is 5.
- 3 parts are shaded, so the numerator is 3.
- The fraction is 3/5.
3. An orange is split into 8 equal segments. Tom eats 2 segments. What fraction is left?
- The orange has 8 equal segments in total.
- Tom ate 2 segments, so 6 segments remain.
- The numerator is 6 and the denominator is 8.
- The fraction left is 6/8.
Try it yourself
A circle is divided into 10 equal parts. 7 parts are coloured blue. What fraction is blue?
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