Greatest common factor, step by step

The greatest common factor is the largest number that divides two values evenly.

The question

GCF of 18 and 30

18:1236918
18:1236918
30:12356101530
18:1236918
30:12356101530
18:1236918
30:12356101530
GCF=6
  1. A factor is a number that divides in exactly. List every factor of 18.
  2. Now every factor of 30.
  3. Some appear in BOTH lists — 1, 2, 3, 6. Those are the common factors.
  4. The greatest of them is 6, so the GCF of 18 and 30 is 6.

How it works.

  1. 01

    A factor is a number that divides in exactly. List every factor of 18.

  2. 02

    Now every factor of 30.

  3. 03

    Some appear in BOTH lists — 1, 2, 3, 6. Those are the common factors.

  4. 04

    The greatest of them is 6, so the GCF of 18 and 30 is 6.