5 | - | 8 |

6 | 9 |

## Step 1: Analyze the operation

This is a subtraction problem, so we need to find two equivalent fractions that have the same denominators. Then we can subtract the numerators.

5 | - | 8 |

6 | 9 |

## Step 2: Find a common denominator

List the multiples of each denominator until a common number is found.

Multiples of `6: 6, 12, 18`

Multiples of `9: 9, 18`

Now we know `18` is the least common denominator of `5/6` and `8/9`.

5 | - | 8 |

6 | 9 |

## Step 3 : Write each fraction with the common denominator

We want the denominator of each fraction to be `18`. But we can't change the denominator without changing the numerator too. To find the new numerator of each fraction, use this formula:

(Common Denominator รท Denominator) x Numerator = New Numerator

Plug in the values of the first fraction into the formula:

`(18 ÷ 6) × 5 = 15`

Re-writing the first fraction, we get `15/18`.

Plug in the values of the second fraction into the formula:

`(18 ÷ 9) × 8 = 16`

Re-writing the second fraction, we get `16/18`.

15 | - | 16 |

18 | 18 |

## Step 4: Subtract the numerators and write over common denominator

Subtract the first numerator and the second numerator:

15 | - | 16 | = | -1 |

18 | 18 | 18 |

The fraction is in lowest terms, and it is proper, so we're done!

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