# Calculate the Greatest Common Factor or GCF of 1305

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The instructions to find the GCF of 1305 are the next:

## 1. Decompose all numbers into prime factors

1305 | 3 |

435 | 3 |

145 | 5 |

29 | 29 |

1 |

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

Prime factors of 1305 | = | 3^{2} . 5 . 29 |

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

Common prime factors: 3 , 5 , 29

Common prime factors with the lowest exponent: 3^{2}, 5^{1}, 29^{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** = 3^{2}. 5^{1}. 29^{1} = 1305

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