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Prime numbers
How far must you divide?
MCQ
To determine whether 221 is prime, up to which divisor must you go at most?
Possible answers
Up to
220
220
220
, i.e.
n
−
1
n - 1
n
−
1
Up to
14
14
14
, because
221
≈
14,9
\sqrt{221} \approx 14{,}9
221
≈
14
,
9
Up to
110
110
110
, i.e. half of
221
221
221
No division test can settle it
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