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Making Change

Posted by michael on from the buddy-can-you-spare-an-eighteener? dept.

Roland Piquepaille writes "There are mostly four kinds of coins in circulation in the U.S: 1 cent, 5 cents, 10 cents, and 25 cents. But is it the most efficient way to give back change? This Science News article says that a computer scientist has found an answer. "For the current four-denomination system, [Jeffrey Shallit of the University of Waterloo] found that, on average, a change-maker must return 4.70 coins with every transaction. He discovered two sets of four denominations that minimize the transaction cost. The combination of 1 cent, 5 cents, 18 cents, and 25 cents requires only 3.89 coins in change per transaction, as does the combination of 1 cent, 5 cents, 18 cents, and 29 cents." He also found that change could be done more efficiently in Canada with the introduction of an 83-cent coin and in Europe with the addition of a 1.33- or 1.37-Euro coin. Check this column for more details and references." The paper (postscript) is online.

5 of 935 comments (clear)

  1. 18 cent coins by Anonymous Coward · · Score: 0, Redundant

    Tell me more about these 18 cent coins!

  2. I would pay 25 cents for an 18 cents coin! by AwesomeJT · · Score: 0, Redundant

    Currently in circulation? Must be a collectors item. I would pay more than the fact value for a coin like that!

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  3. REDUNDANT: 18-cents by p3d0 · · Score: 0, Redundant

    I hereby declare any future posts mentioning the "18" typo redundant, including this one. Please mod accordingly.

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    Patrick Doyle
    I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
  4. Re:I hate math... by Lt+Razak · · Score: 0, Redundant

    Yea right, if that happened, then inflation would speed up and the nickel would be just like the penny is now.

  5. ARGH! Bit by HTML again. Here's the full example by Ungrounded+Lightning · · Score: 0, Redundant

    Oops. I forgot that slashdot would think the amounts in angle-brackets were HTML tags, rather than straight text. Let's try that example again.

    Example: $1.33 sale from $20

    one thirty three.
    (penny) [one] thirty four
    (penny) [one] thirty five
    (nickel) [one] forty
    (dime) [one] fifty
    (quarter) [one] seventy five
    (quarter) two dollars
    (dollar bill) and three
    (dollar bill) and four
    (dollar bill) and five
    (five dollar bill) and five makes ten
    (ten dollar bill) and ten makes twenty

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