Make use of GCF Calculator to quickly find the Greatest Common Factor of numbers 80, 81 i.e. 1 largest integer by which both the numbers can be divided.

Greatest common factor (GCF) of 80 and 81 is **1**.

GCF(80,81) = 1

*Greatest common factor* or Greatest common divisor (GCD) can be calculated in following way;

- Greatest Common Factor of 80 and 81 by prime factorization method
- Greatest Common Factor of 80 and 81 by matching factors method

**Prime Factorization of 80**

2 | 80 |

2 | 40 |

2 | 20 |

2 | 10 |

5 | 5 |

1 |

Prime factors of 80 are 2,5. Prime factorization of **80** in exponential form is:

80 = 2^{4}×5^{1}

**Prime Factorization of 81**

3 | 81 |

3 | 27 |

3 | 9 |

3 | 3 |

1 |

Prime factors of 81 are 3. Prime factorization of **81** in exponential form is:

81 = 3^{4}

∴ So by taking common prime factors GCF of 80 and 81 is 1

**Factors of 80**

List of positive integer factors of 80 that divides 80 without a remainder.

1,2,4,5,8,10,16,20,40,80

**Factors of 81**

List of positive integer factors of 81 that divides 81 without a remainder.

1,3,9,27,81

**Greatest Common Factor**

We found the factors and prime factorization of 80 and 81. The biggest common factor number is the **GCF** number.

So the **greatest common factor 80 and 81** is **1**.

Also check out the Least Common Multiple of 80 and 81

(i) The GCF of 80 and 81 is associative

GCF of 80 and 81 = GCF of 81 and 80

1. What is the GCF of 80 and 81?

Answer: GCF of 80 and 81 is 1.

2. What are the Factors of 80?

Answer: Factors of 80 are 1, 2, 4, 5, 8, 10, 16, 20, 40, 80. There are 10 integers that are factors of 80. The greatest factor of 80 is 80.

3. What are the Factors of 81?

Answer: Factors of 81 are 1, 3, 9, 27, 81. There are 5 integers that are factors of 81. The greatest factor of 81 is 81.

4. How to Find the GCF of 80 and 81?

Answer:

Greatest Common Factor of 80 and 81 = 1

Step 1: Find the prime factorization of 80

80 = 2 x 2 x 2 x 2 x 5

Step 2: Find the prime factorization of 81

81 = 3 x 3 x 3 x 3

Step 3: Multiply those factors both numbers have in common in steps i) or ii) above to find the gcf:

GCF = = 1

Step 4: Therefore, the greatest common factor of 80 and 81 is 1