# Calculate the Greatest Common Factor or GCF of 54, 20 and 8

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The instructions to find the GCF of 54, 20 and 8 are the next:

## 1. Decompose all numbers into prime factors

54 | 2 |

27 | 3 |

9 | 3 |

3 | 3 |

1 |

20 | 2 |

10 | 2 |

5 | 5 |

1 |

8 | 2 |

4 | 2 |

2 | 2 |

1 |

## 2. Write all numbers as the product of its prime factors

Prime factors of 54 | = | 2 . 3^{3} |

Prime factors of 20 | = | 2^{2} . 5 |

Prime factors of 8 | = | 2^{3} |

## 3. Choose the common prime factors with the lowest exponent

Common prime factors: 2

Common prime factors with the lowest exponent: 2^{1}

## 4. Calculate the Greatest Common Factor or GCF

Remember, to find the GCF of several numbers you must multiply the common prime factors with the lowest exponent.

**GCF** = 2^{1} = 2

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