Question: how many numbers between 1 and 100 have 5 ones?
Answer: I believe the digit (number) 5 appears 20 times. (5,15,25,35,45,50,51,52,53,54,55,56,57,58,59,65,75,85,95) count the 5's that appear. Answer: 20 times digit 5 is used between 1 and 100.