Given two numbers a and b, determine if the product ab is a permutation of the digits of a. For example, this is always true for a=0. Less trivially, 125874*2=251748.

If the product, ab, has more digits than a, append zeros to the front of a so they have the same number of digits. Thus, for example, 015*7=105 is another example.

This problem was inspired by seeing a student simplify 163/326 to 1/2 by cancelling out the digits in common.