Add and subtract factions with the same denominator

Adding two fractions with the same denominator is straightforward:

  • Add the numerators (top numbers)
  • Don't add the denominators (bottom number). This stays the same.
  • Simplify the fraction if required.


What is \(\frac{2}{7} + \frac{4}{7}\)?

  • Add the numerators: \(\frac{2}{7} + \frac{4}{7} = \frac{6}{\,}\)
  • Don't add the denominators: \(\frac{2}{7} + \frac{4}{7} = \frac{6}{7}\)
  • Simplify the fraction if required: \(\frac{6}{7}\) is already in its simplest form.

Subtracting fractions with the same denominator can be done in the same way.

Try it out with these sample questions.


Calculate the following:

  1. \[\frac{2}{3} - \frac{1}{3}\]
  2. \[\frac{4}{5} - \frac{2}{5}\]
  3. \[\frac{7}{10} - \frac{3}{10}\]
  1. \[\frac{2}{3} - \frac{1}{3} = \frac{1}{3}\]
  2. \[\frac{4}{5} - \frac{2}{5} = \frac{2}{5}\]
  3. \(\frac{7}{10} - \frac{3}{10} = \frac{4}{10}\). This can be simplified to \(\frac{2}{5}\)