Practice question · Select all that apply
Select every integer below that divides 84.
Hints
- 84 = 2 x 2 x 3 x 7, every divisor must be built from those prime factors.
- 84 contains only two 2s, so no divisor can need three of them.
Show the answer
- A. 12
- D. 21
- E. 6
- F. 14
Why
84 = 2 x 2 x 3 x 7. So 6 = 2 x 3, 12 = 2 x 2 x 3, 14 = 2 x 7 and 21 = 3 x 7 all divide it. But 8 needs three 2s and 16 needs four, and 84 only has two, divisibility is decided by the prime supply, not by size.
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