Sorry! I definitely should have added some comments.

The first section deals with zeros. ABS(SIGN()) for minus numbers or positive numbers being 1 and zero being 0 so the MIN will...

And another way to deal with 0 and negatives it if you don't want to use a 'case' statement :

MIN(ABS(SIGN(num))) * (1-(SUM(SIGN(num) * (SIGN(num) -1))%4)) * POWER(10.,SUM(LOG10(ABS(Num) + 1 -...