6. Look at several examples of rational numbers in the form qp (q ! 0), where p and q are integers with no common factors other than 1 and having terminating decimal representations (expansions). Can you guess what property q must satisfy?

To represent rational number qp (q ! 0) in terminating decimal form it is necessary to choose denominator q such that its prime factorization must has only powers of 2 or powers of 5. For example (i) 167 is a terminating decimal because 16 = 24 (ii) 1125 is a terminating decimal because 25 = 52