How many fives are between 1 and 100?

5, 15, 25, 35, 45, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 65, 75, 85, 95. By counting them, there are twenty 5s between 1 and 100.

Actually...if by "between" the questioner intended to exclude the number 100, then there are only 19 5s "between" 1 and 100.