Subtract the two fractions.

Two fractions are subtracted by expanding them to the common denominator and then subtracting their numerators.

Check whether the result can be simplified.

If you would like to have a vivid explanation with a detailed example, please read the page Subtraction Fraction minus Fraction - The Thought Experiment

**Step 1: Determine the common denominator:**

The common denominator is equal to the lowest common multiple (LCM) of the two denominators: 8 is a multiple of 4. Therefore the common denominator is **8**

**Step 2: Expand to the common denominator:**

Expand the first fraction with the number 2

1 | - | 1 | = | 1 × 2 | - | 1 | = | 2 | - | 1 |

| | | | | |

4 | 8 | 4 × 2 | 8 | 8 | 8 |

**Step 3: Subtract the numerators:**

Since the two fractions have a common denominator, you can subtract:

2 | - | 1 | = | 2 - 1 | = | 1 |

| | | |

8 | 8 | 8 | 8 |

**Step 4: Check whether the result can be simplified**

The result can not be simplified.