How many positive integers less than 100 have reciprocals with terminating decimal representations???
This is equivalent to the question what positive integers less than 100 have only 2 and 5 as prime factors.
listing these isn't too hard
2, 4, 8, 16, 32, 64
5, 10, 20, 40, 80
25, 50
so 13 of them
+2864 
