The GCD of given numbers is 12.
Step 1 : Place the numbers inside division bar:.
| 72 | 108 | 2100 |
Step 2 : Divide numbers by 2.
| 2 | 72 | 108 | 2100 |
| 36 | 54 | 1050 |
Step 3 : Divide numbers by 2.
| 2 | 72 | 108 | 2100 |
| 2 | 36 | 54 | 1050 |
| 18 | 27 | 525 |
Step 4 : Divide numbers by 3.
| 2 | 72 | 108 | 2100 |
| 2 | 36 | 54 | 1050 |
| 3 | 18 | 27 | 525 |
| 6 | 9 | 175 |
Step 5 : Number 6, 9 and 175, cannot be divided any more. The GCD is:
$$ GCD = 2\cdot2\cdot3 = 12 $$This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.