Simple Fraction Sums

Add and subtract fractions with the same denominator within one whole (e.g. 5/7 + 1/7 = 6/7)

ages 7 to 88 practice questionsvideo included

What a learner can do afterwards

Calculate 2/5 + 2/5 = 4/5
Calculate 6/8 − 3/8 = 3/8
Explain that when denominators are the same, you add/subtract the numerators

The lesson

A fraction has two numbers. The bottom number tells how many equal parts make one whole. The top number tells how many of those parts you have. When two fractions have the same bottom number, adding or subtracting them is easy. Just add or subtract the top numbers. The bottom number stays exactly the same.

Tap to shade 2 of the 5 parts.

This bar is cut into 5 equal parts. 2 of them are shaded, so this shows 2/5.

Try it together

Ravi eats 2/5 of a pizza at lunch. Later he eats another 2/5 of a same-size pizza. Both fractions have a bottom number of 5, so he just adds the top numbers: 2 + 2 = 4. Ravi ate 4/5 of a pizza in total.

Tap to shade 4 of the 5 parts.

Good to know

Never add or subtract the bottom numbers. Only the top numbers change. 2/5 + 2/5 is 4/5, not 4/10.

Same bottom number? Just add or subtract the top numbers, and keep the bottom number the same.

Watch it

Where it sits

Learn first

Fractions on a number line Addition as combining or putting together two

This opens up

Adding Fractions (Same Denominator)Understanding fractions (age 7+)Comparing fractions (age 7+)

Where this leads

Jobs that lean on this skill. Follow one to see everything it is built on.

Baker Chef Dancer Music Producer Musician

Then practise

8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.