Add and subtract fractions with the same denominator KS2 Revision
What you need to know
Things to remember:
- If we add or subtract two fractions with the same denominator, we can just add or subtract the top numbers.
- If we add or subtract two fractions with the same denominator, the denominator in the answer will be the same as the denominator in the question.
Let’s recap a little, below we have a fraction of a grid shaded in and what this means in terms of numbers.
=\frac{3}{6}
Here, the numerator is 3, and the denominator is 6.
If two fractions have the same denominator, we can actually just add them straight away
\frac{3}{6} + \frac{2}{6}= \frac{5}{6}
Because our two fractions have been split into the same amount, so is the answer, so the denominators stay the same! We have added 3 sixths and 2 sixths, to give us a total of 5 sixths. We can do the same with subtraction.
\frac{3}{6} - \frac{2}{6}= \frac{1}{6}
Example Questions
Question 1: Find the answer to:
\frac{3}{8} + \frac{1}{8}
\frac{3}{8} + \frac{1}{8}=\frac{4}{8}
So, the answer is \frac{4}{8}
Question 2: Find the answer to:
\frac{7}{9} - \frac{5}{9}
\frac{7}{9} - \frac{5}{9}=\frac{2}{9}
So, the answer is \frac{2}{9}