Find Greatest Common Divisor of 21, 42 and 84, using repeated division.
Answer
The GCD of given numbers is 21.
Explanation
Step 1 : Place the numbers inside division bar:.
| 21 | 42 | 84 |
Step 2 : Divide numbers by 3.
| 3 | 21 | 42 | 84 |
| 7 | 14 | 28 |
Step 3 : Divide numbers by 7.
| 3 | 21 | 42 | 84 |
| 7 | 7 | 14 | 28 |
| 1 | 2 | 4 |
Step 4 : Number 1, 2 and 4, cannot be divided any more. The GCD is:
$$ GCD = 3\cdot7 = 21 $$This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.
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