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Lesson overview

Number - fractions

When fractions have the same denominator, the whole is split into the same size parts. We keep the denominator the same and add or subtract the numerators.

Add eighths

$\frac{2}{8} + \frac{3}{8} = \frac{5}{8}.$

The denominator stays as 8 because the parts are still eighths.

Subtract tenths

$\frac{7}{10} - \frac{2}{10} = \frac{5}{10}.$

Subtract the numerators and keep the denominator.

Equal parts matter

This method works when the fractions have the same denominator.

The parts must match in size.

Worked example

Work out $\frac{4}{12}$ + $\frac{5}{12}$ .

Check that both fractions have the same denominator.
They are both twelfths, so the parts are the same size.
Add the numerators: 4 + 5 = 9.
So the answer is $\frac{9}{12}$ .

Round 1: Learn it

Keep the denominator the same and work carefully with the numerators.

Finish this round to unlock Round 2: Show you know it.

Question 1

What is $\frac{2}{6}$ + $\frac{3}{6}$ ?

Question 2

What is $\frac{9}{10}$ - $\frac{4}{10}$ ?

Question 3

Write the numerator in $\frac{5}{8}$ + $\frac{2}{8}$ = $\frac{7}{8}$ .

Question 4

Which answer is correct for $\frac{11}{12}$ - $\frac{3}{12}$ ?

Question 5

What stays the same when we add fractions with the same denominator?

Common mistakes

Watch for these as you work through the lesson.

Changing the denominator when the parts stay the same size.
Adding or subtracting the denominator as well.
Using the rule when the denominators are different.

Add and subtract fractions with the same denominator

Lesson overview

Worked example

Round 1: Learn it

Common mistakes

Related topics

Independent practice will plug in here