rename these functions
move this to product code so we can use it later
make it take multiple values
solve euler problem 52
add a couple more test cases
this deserves separate files
this deserves its own function
and to be in the product
another test case
this is a separate function too methinks
these are of general use
these are the natural numbers
use our new library function
cut out a bunchof code and improve a test name
this is a common question we ask too