Which of the following produce terminating decimals for all integers n?
2. The attempt at a solution
I read on the internet that reduced fraction a/b (meaning that fraction is already reduced to its lowest term) can be expressed as terminating decimal if and only if b (denominator) is of the form 2^n5^m, where m and n are non-negative integers.
That would mean only n/10 and n/12 are the answers. But I don't really understand why only denominators in the form 2^n5^m work?
Can someone explain please?