| I don't know why they don't make threes. Anyone could have told them that prime numbers, as in 1, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37 etc. are numbers that make up any other number, so you don't need any other bills. 4, 6, 8, 9, 10, 12, 14, 15, 18, 21, 24, 25, 26, 27, 28 can all be made from the primes, so there is no necessity of having even number bills. The prime bills would be divisors of all quantities, and form the least number of denominations necessary to make up all amounts, accounting for the least change. Duodecimal systems have more divisors thus come out even more often than ten based as well. For change you would have 1, 2, 3, 5, 7, 17, 18, 23, 29 cent pieces and a 47, and 79 cent piece. If a person proffers 3.50 in change for a 2.79 item, you give them 19, 5, and 47 C in change. Easy. Otherwise it would be 10,10, 1, and 25 and 25. Two more pieces. |
