The GCD of given numbers is 9.
Step 1 : Place the numbers inside division bar:.
| 18 | 27 | 45 |
Step 2 : Divide numbers by 3.
| 3 | 18 | 27 | 45 |
| 6 | 9 | 15 |
Step 3 : Divide numbers by 3.
| 3 | 18 | 27 | 45 |
| 3 | 6 | 9 | 15 |
| 2 | 3 | 5 |
Step 4 : Number 2, 3 and 5, cannot be divided any more. The GCD is:
$$ GCD = 3\cdot3 = 9 $$This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.