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How to add and subtract fractionsAdd and subtract factions with the same denominator

Adding and subtracting can be applied to mixed number fractions. Each has its own method that helps make sure the numerator and denominator are treated correctly.

Part of MathsFractions, decimals and percentages

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.

Example

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.

Question

Calculate the following:

  1. \(\frac{2}{3} - \frac{1}{3}\)
  2. \(\frac{4}{5} - \frac{2}{5}\)
  3. \(\frac{7}{10} - \frac{3}{10}\)

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Add and subtract factions with different denominators

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