Happy New Year 2013

One of the questions that may be asked about our new year is whether 2013 is composite or prime -- that is, whether it does or does not have factors other than 1 and the number itself.  A shortcut useful here is this test for divisibility by 3 (offered as a 5x5 square):

        An integer is
        divisible by
        3 if and only
        if the sum of its 
        digits is also.

And so, since 2 + 0 + 1 + 3 = 6 (which is divisible by 3), then 2013 is divisible by 3.  Indeed, the prime factorization is 2013 = 3 x 11 x 61.

My email on this New Year's morning contained a gift -- "Digits" -- a poem that compares numbers with nature, from Virginia poet and dream specialist Joan Mazza;  she has given me permission to post it here. 

     Digits     by Joan Mazza