Why can't numbers composed of a single digit be prime? Why is it that a number composed of only 1's can be prime. Why not 2,3,4, or any other digit? I seem to believe the the only prime composed of 1's is 11. Is this true?
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Question

Why can't numbers composed of a single digit be prime? Why is it that a number composed of only 1's can be prime. Why not 2,3,4, or any other digit? I seem to believe the the only prime composed of 1's is 11. Is this true?
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anonymous · Answer

1. They can. 2,3,5, and 7 are all single-digit prime numbers.
2. This is because 1 is the smaller number. 11 has no numbers that fit into it. But for 22 r 33, 11 fits into those. 11*2=22 and 11*3=33.
3. 111, 1,111, 11,111 are all prime numbers made of 1. You can have any number of 1's and they will all be prime numbers.
I hope this answers your questions.