Adding and subtracting fractions
I can add and subtract fractions, and swap between improper fractions and mixed numbers.
For grown-ups: this lesson in words
Years 3 to 6 · Maths
Adding and subtracting fractions: I can add and subtract fractions, and swap between improper fractions and mixed numbers.
Think of this circle as a pizza. It is cut into 8 equal slices.
Mei eats 3 slices. The shaded part shows how much she ate.
We write it as 3/8: 3 slices out of 8 equal slices.
The bottom number, 8, is the denominator. The top number, 3, is the numerator.
Picture: A circle cut into 8 equal parts, with 3 parts shaded. It is labelled 3/8.
Now add 2/8 more. Here is a number line marked in eighths. Start at 3/8.
Hop on 2 eighths: 4/8, then 5/8.
3/8 + 2/8 = 5/8
Add the top numbers: 3 + 2 = 5. The bottom number stays 8, because the parts are still eighths.
Picture: A number line from 0 to 1 marked in steps of 1/8. A dot at 3/8 labelled "start". The frog hops from 3/8 to 4/8 (+1/8), then to 5/8 (+1/8).
Your turn: Zara has eaten 1/6 of this chocolate bar. That is the shaded part. She eats 2/6 more. Shade the bar to show 1/6 + 2/6.
Picture: A bar cut into 6 equal parts, with 1 part shaded.
Set the picture to your answer.
Answer
The answer: 3
1/6 + 2/6 = 3/6. Three parts out of 6 are shaded.
Picture: A bar cut into 6 equal parts, with 3 parts shaded. It is labelled 3/6.
Words to know
- denominator:
- The bottom number. It says how many equal parts the whole is cut into.
- numerator:
- The top number. It says how many of the parts we have.
- improper fraction:
- A fraction with a top number bigger than its bottom number, like 5/4.
- mixed number: