Subtraction of Fractions Calculator

Published on: March 3, 2024
Final Answer: Free • Full Steps: Free

This Subtraction of Fractions Calculator helps you subtract fractions and shows the working clearly step by step. First find a common denominator, then rewrite the fractions so they have the same bottom number. Subtract the numerators, keep the denominator the same, and simplify the final fraction if possible. It is a simple way to check answers, understand fraction subtraction, and practise basic arithmetic step by step.

Step-by-step method

  1. Set up the problem. Write the two fractions with a minus sign between them.
  2. Make the bottom numbers match. (Find a common denominator.)
  3. Subtract the top numbers. Keep the bottom number the same.
  4. Simplify the final fraction (only here).

Example 1: \(\frac{3}{4} - \frac{1}{2}\)

Step 1 - Set up the problem. Write the two fractions with a minus sign between them.

In this problem: We are subtracting \(\frac{1}{2}\) from \(\frac{3}{4}\).

\(\frac{3}{4} - \frac{1}{2}\)

Step 2 - Make the bottom numbers match. (Find a common denominator.)

In this problem: The bottom numbers are \(4\) and \(2\). A good shared bottom number is \(4\). So we change both fractions into equal fractions with the same bottom number.

\(\frac{3}{4} \times 1 = \frac{3}{4}\)
\(\frac{1}{2} \times \frac{2}{2} = \frac{2}{4}\)

Step 3 - Subtract the top numbers. Keep the bottom number the same.

In this problem: Now both fractions have bottom \(4\), so we subtract the top numbers: \(3 - 2 = 1\).

\(\frac{3}{4} - \frac{2}{4} = \frac{1}{4}\)

Step 4 - Simplify the final fraction (only here).

In this problem: This fraction is already in simplest form.

\(\frac{1}{4}\)

Final answer: \(\frac{3}{4} - \frac{1}{2} = \frac{1}{4}\)

Example 2: \(\frac{5}{18} - \frac{2}{10}\)

Step 1 - Set up the problem. Write the two fractions with a minus sign between them.

In this problem: We are subtracting \(\frac{2}{10}\) from \(\frac{5}{18}\).

\(\frac{5}{18} - \frac{2}{10}\)

Step 2 - Make the bottom numbers match. (Find a common denominator.)

In this problem: The bottom numbers are \(18\) and \(10\). A good shared bottom number is \(90\). So we change both fractions into equal fractions with the same bottom number.

\(\frac{5}{18} \times \frac{5}{5} = \frac{25}{90}\)
\(\frac{2}{10} \times \frac{9}{9} = \frac{18}{90}\)

Step 3 - Subtract the top numbers. Keep the bottom number the same.

In this problem: Now both fractions have bottom \(90\), so we subtract the top numbers: \(25 - 18 = 7\).

\(\frac{25}{90} - \frac{18}{90} = \frac{7}{90}\)

Step 4 - Simplify the final fraction (only here).

In this problem: This fraction is already in simplest form.

\(\frac{7}{90}\)

Final answer: \(\frac{5}{18} - \frac{2}{10} = \frac{7}{90}\)