Question: how many a in 1 to 100?
Answer: They are 10, 11,12, 13, 14, 15, 16, 17, 18, 19, 21, 31,41, 51, 61, 71, 81, 91. There are 18 not counting 1 and 100, because as per the wording of the question 'between' means 1 and 100 are not to be included. So, there are 21 ones from 1 to 100.