We have two sets of numbers:
1 2 3
3 4 6
... and we wish to compare them.
Divide each (higher) digit, from the other (lower) digit.
3/1=3
4/2=2
6/3=2
Times out the answer:
3*2*2 = 12
This gives us a comparison function that can be used with qsort.
The closer the value is to 1, the more similar they are.