Question

Each of the positive integers from 1 to 100 are written on a sheet of paper.

Some of these integers are erased. The product of those integers still on the paper leaves a remainder of 4 when divided by 5. Find the least number of integers that could have been erased.

Answer 1

9 14 19 24 29 34 39 44 49 54 59 64 69 74 79 84 89 94 99