Find the least number of coins required that can make any change from 1 to 99 cents

Question

Recently I challenged my co-worker to write an algorithm to solve this problem:

Find the least number of coins required that can make any change from

Answer 1

As I understood if you are using standard currency system values then its super easy to count the minimum number of coins just by a single loop. Just always consume the max coin value and if it not possible check for the next option. But if you have a system like you have coins such as 1,2,3,4 then its not working. I guess the whole idea of having coins as 1,2,5,10,25 is to make computation easy for humans.