Question 886047
The set of all counting numbers less than 15 is
{1,2,3,4,5,6,7,8,9,10,11,12,13,14}
Take out the evens
{1,3,5,7,9,11,13} <<-- odd counting numbers less than 15
Go further.  Which are prime?
{1,3,5,7,11,13}