Enter denominations of coins:
Calculate from: to
DenominationAve. received
25 1.50
10 0.80
5 0.40
1 2.00
Average coins4.70

The point of this exercise is to reduce the number of coins that the average person has to carry around in their pockets. Above, you may enter the coins that are in circulation in your country (don't worry about the order; I'll sort them.)

The default you see above (25, 10, 5, 1) are the coins commonly in circulation in the United States. On an average transaction, we get 4.70 coins back if we don't carry exact change (see the "average coins" in bold above.) That's a lot. We get 2 pennies back in the average transaction. Add a "2" to the "denomination of coins" field above to see how many coins we'd get if we also had a 2-cent coin. Is it less than 4.70? If so, that would be an improvement! How about if we had 50-cent pieces in circulation?

Your task, should you choose to accept it, is to find the best combination of coins to reduce the number of coins that people have to carry. A low score in the "average coins" field is good. What if there are 5 different denominations? Seven?

What if we eliminated the one-cent piece and rounded everything to the nearest 5 cents? (Just delete the "1" in the "denomination of coins" field above.)

What if our smallest bill was five dollars? (Change the "99" to "499" in that case.) Have fun!

Can you come up with a procedure to find the best coin denominations, if the mint only wants to make 5 different coins? 6 different coins? x number of different coins?

What countries have the most efficient systems? E-mail me your best scores!

Comments, questions to Alan Eliasen

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