Question

Write the nature of factors of denominator of a rational number which has terminating decimal expansion

Answer 1

The actual nature of factors of denominator of a rational number should be such that when we do the prime factorization of the overall rational number, the overall form should be in the form of 2 raised to the power of "m" multiplied by 5 raised to the power of "n".  

This is a simple rule.

Only in such cases, we can say that the particular rational number would have a terminating decimal expansion, and not otherwise.  

In each of the cases, the value of m and n should be anything, but they have to be non-negative integer definitely.