So what is the fewest number of coins you can carry that allows you to produce any exact change?The answer is 10 coins, 3 Quarters, 1 dime, 2 nickel, and 4 pennies. With this combination you can produce any number between 1-99 cents.



An alternative answer would be 6 coins, 3 Quarters, 2 dimes and 1 nickel. In this example you will range most change between 5-95 cents, in 5 cents increments. In this example you will never receive more than 4 cents in change back.



The project is a way to carry these 10 coins easily inside your wallet. I have used a thin piece of cardboard. But if you may use most anything, I recommend any material about 2 stacked coins thick, and have enough friction to hold the coins in place.