If the number is a multiple of ten, then its last digit must be ' 0 '.
If one of its digits is ' 3 ', then that must be the first one,
and the whole 2-digit number must be ' 30 '.
I believe that's the only possibility. I'll be very interested to see
somebody else come up with a 2-digit number that's a multiple
of 10, has 3 as one of its digits, and isn't 30 .
