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Making Change

michael posted more than 11 years ago | from the buddy-can-you-spare-an-eighteener? dept.

The Almighty Buck 1129

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.

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I hate math... (5, Funny)

Swannie (221489) | more than 11 years ago | (#5972431)

I think the advantage to having a 10-cent piece is that it makes the math easy. Let's face it; can you imagine the average cashier at WalMart giving back 98 cents change with an 18-cent coin?

Swannie

Re:I hate math... (0)

Anonymous Coward | more than 11 years ago | (#5972440)

Yep, those 18 cent coins are a bitch. Why didn't they just use 10 cent pieces instead?

Re:I hate math... (1)

Mondoz (672060) | more than 11 years ago | (#5972510)

Nothing like a good typo to derail the entire article...

Re:I hate math... (0)

Yoje (140707) | more than 11 years ago | (#5972443)

can you imagine the average cashier at WalMart giving back 98 cents change with an 18-cent coin?

I guess the story submitter can as they listed an 18c coin as one in regular US circulation!

Re:I hate math... (2, Funny)

Anonymous Coward | more than 11 years ago | (#5972479)

Well, I can certainly imagine that. Let's see, 98 cents, that's two 40ct pieces and one 18ct piece. Easy.

Re:I hate math... (3, Insightful)

Anonymous Coward | more than 11 years ago | (#5972487)

That's part of the process that doesn't seem to have been looked at well. While the model of 'giving change' may include a number of coins, it also includes the entire process including a cashier translating the change amount into coinage, then counting it back to the customer, and much of the time, the customer counting and checking it's the right amount.

For the pure maths side of it it's pretty neat, all the same - just not completely useful when it comes to Real World Stuff

Re:I hate math... (-1)

Real World Stuff (561780) | more than 11 years ago | (#5972569)

True, I do not find it useful at all! :)

Re:I hate math... (0)

Anonymous Coward | more than 11 years ago | (#5972501)

I think you're on to something. How about a 99ct coin?

**CAUTION**:: Shitty Story ahead. Dont clik linkz. (-1, Offtopic)

Anonymous Coward | more than 11 years ago | (#5972538)

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Re:I hate math... (0)

jez9999 (618189) | more than 11 years ago | (#5972591)

Uhm... do you people SERIOUSLY have an 18 cent coin?? I thought it was a typo, but if so it's typoed 3 times, identically, in the same submission. Either you have 18 cent coins (I don't remember seeing any when I went to america) or some asshole has been *criminally* negligent in copy/pasting those coin values, and not bothering to check what they said.

eighteen cents? (0)

mrbill (4993) | more than 11 years ago | (#5972433)

Wouldn't it be 10 cents, instead of 18 cents?

Re:eighteen cents? (1)

Baby_with_a_nailgun (669757) | more than 11 years ago | (#5972488)

Wouldn't it be 10 cents, instead of 18 cents?

Article says that an 18-cent coin would make more sense, but yes the summary is a bit muddled up.

18 cents? (0, Redundant)

RayMarron (657336) | more than 11 years ago | (#5972435)

Sure that wasn't a slashed zero?

18 cents? (-1, Redundant)

Anonymous Coward | more than 11 years ago | (#5972436)

Oh really now?

Re:18 cents? (1)

Lane.exe (672783) | more than 11 years ago | (#5972550)

18 Cents is all the rage in the pop-rap world these days...

ummm..18 cent coin? (0, Redundant)

omarKhayyam (544074) | more than 11 years ago | (#5972442)

hmm...somehow I missed that one :).

Forget it. (1, Insightful)

grub (11606) | more than 11 years ago | (#5972445)


More and more transactions are done electronically. Does anybody really want to go back to shilling, farthings, etc etc?

Re:Forget it. (2, Funny)

Ripplet (591094) | more than 11 years ago | (#5972468)

Exactly. All you need is a 1 cent coin, and a, er, zero cent coin!

Yeah Right... (5, Funny)

IpsissimusMarr (672940) | more than 11 years ago | (#5972447)

Are you kidding me?!

Have you ever gotten a bill for dinner for say $12.50 and you give the cashier $15 saying the tip is included?
You would think 15.00 - 12.50 is doable right?

HELL NO! The cashier pulls out a calculator to do the math so she can write it in for the waiter's tips!!!

If people can't add things like this 18cent coins are out of the question.


Although I would like to hear a cashier go,
"That makes $0.88 change sir." Pick out two quarters then, ... *pause* .... and just stare blankly at the change drawer.

Re:Yeah Right... (1)

bigox (158657) | more than 11 years ago | (#5972549)

Just be happy that they aren't Pi coins.

Re:Yeah Right... (1)

swillden (191260) | more than 11 years ago | (#5972589)

The cashier pulls out a calculator to do the math so she can write it in for the waiter's tips!!!

So what you're saying is that it really makes no difference whether the coinage is in nice multiples of fives and tens. They're going to use a calculator either way...

Re:Yeah Right... (5, Funny)

ip_vjl (410654) | more than 11 years ago | (#5972602)

One time at a grocery/conveneience store, I had a total come to something like $1.87

Wanting to minimize some of the change in my pocket, I gave the clerk $2.00 in bills and 12 cents.

The clerk tried to hand it back, saying "it's only $1.87"

I said, "yes, but this way, I'll get a quarter back in change."

He took the money, punched it into the cash register, and as he handed me back the quarter, he said "How did you know that?"

It's funny (in a VERY sad way) that to him, the cash register was this magic oracle that told him what to do, and that it didn't occur to him that what he was doing was even knowable without its use.

D'oh! (3, Funny)

aitala (111068) | more than 11 years ago | (#5972448)

Is it too early in the morning or does this article not make sense? I have never seen an 18 cent piece in circulation n the US...

Re:D'oh! (4, Funny)

Trailer Trash (60756) | more than 11 years ago | (#5972528)

Is it too early in the morning or does this article not make sense? I have never seen an 18 cent piece in circulation n the US...

I'm waiting to see if Taco screws it up in the dup tomorrow, too...

MDC

Re:D'oh! (1)

Mysticalfruit (533341) | more than 11 years ago | (#5972590)

[SALES PITCH VOICE]

This limited edition rubix zarconium triple winged eagle 18c coin is of legal tender in the U.S.

It can be yours for only 29.99 plus shipping and handling.

Limited 3.98 per customer, supplies limited, call now!

[/SALES PITCH VOICE]

18 cent coins (0, Redundant)

Anonymous Coward | more than 11 years ago | (#5972451)

Tell me more about these 18 cent coins!

Re:18 cent coins, More info... (0)

Anonymous Coward | more than 11 years ago | (#5972564)

These 18 cent coins are a rare find indeed! There arent many around... But if you look hard enough you will find them.

Ok joking aside... I think he meant to type 10... but he did it more than once.... so who knows.. anything is possible I guess...

fractional coins (-1, Flamebait)

The Terrorists (619137) | more than 11 years ago | (#5972452)

The benefit is greatly outweighed by the cost. This can probably be done in metric Europe which has a decent, standardized school system. Not in the unevenly educated and radically, completely math-ignorant United States.

Re:fractional coins (0)

Anonymous Coward | more than 11 years ago | (#5972529)

This would be just as stupid in Europe as it would be here. I can't believe that people are so much better at math there, that they want to divide by 18, 29, or 83. Unless that standardized schooling makes them crazy.

What bugs me most, is that we could get most of the benefit of these system by elimnating pennies.

18 cent coin?? (5, Funny)

Anonymous Coward | more than 11 years ago | (#5972454)

My God...have I been playing Everquest that long?

18 cent dimes? (0, Redundant)

Neppy (673459) | more than 11 years ago | (#5972455)

Dimes are worth 18 cents?

Re:18 cent dimes? (2, Funny)

ClippyHater (638515) | more than 11 years ago | (#5972520)

On e-bay, with a good enough of a write-up and screenshots galore, I bet you could even get $1 for a dime!

I've never seen an 18-cent piece before. (0)

Anonymous Coward | more than 11 years ago | (#5972456)

Duhhhhh. "Let's try communicatin' wit it."

"Don't get too close, or you'll catch its stupid!"

The radio.weblog.com link already slow, heres text (-1, Redundant)

Anonymous Coward | more than 11 years ago | (#5972458)

This Science News [sciencenews.org] article says that a computer scientist has found an answer.

In the current issue of the Mathematical Intelligencer, [Jeffrey Shallit of the University of Waterloo] contends that "what the U.S. needs is an 18-cent piece."
In finding coin denominations that minimize the average cost of making change, Shallit assumed that every amount of change between 0 and 99 cents is equally likely. For the current four-denomination system, he found that, on average, a change-maker must return 4.70 coins with every transaction.
He discovered two sets of four denominations that michael sucks and 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.

Of course, it would be more difficult for cashiers to give you back your change. So, instead of replacing one of the existing four coins, Shallit played with the hypothesis of the addition of a fith coin.

It turns out that the greatest improvement in change-making efficiency would occur with the addition of a 32-cent coin. This reduces the average cost to 3.46 coins per transaction.

Is this a crazy idea? Other coins existed in the past.

The United States has experimented briefly with extra coin denominations. At one time or another in the distant past, the U.S. mint issued half-cent, two-cent, three-cent, and 20-cent pieces--but it never produced an 18-cent coin.

Obviously, this optimization of change can also be done in other countries.

[In Canada,] Shallit's calculations show that the average cost of making change would fall from 5.90 to 4.58 coins per transaction with the addition of an 83-cent coin.
Similarly, the new Euro system introduced by the European Union would benefit from the addition of a 1.33- or 1.37-Euro coin.

For more information, please read Shallit's paper, What this country needs is an 18-cent piece [uwaterloo.ca] .

Source: Ivars Peterson, Science News, Week of May 10, 2003; Vol. 163, No. 19


Rarity (0)

Anonymous Coward | more than 11 years ago | (#5972460)

That must be a damn rare 18 cent coin you got there.

Instead... (5, Insightful)

frodo from middle ea (602941) | more than 11 years ago | (#5972463)

Why not just get rid of silly prices like 99.99 and 4.37 and 1.49. ?
Why not round prices to dimes ? Or even quarters ?

Re:Instead... (2, Insightful)

Bazman (4849) | more than 11 years ago | (#5972482)

Because retailers would round _upwards_.

Re:Instead... (3, Insightful)

xyzzy (10685) | more than 11 years ago | (#5972545)

Fine, who cares, let them! For god's sake, they're fooling no one. In addition, they should incorporate sales tax INTO the price so that the price you see is the price you pay. If an article is $4, it's $4! No change necessary!

Re:Instead... (1)

soccerisgod (585710) | more than 11 years ago | (#5972490)

Marketeers consider those prices psychologically important, because they make prices appear lower than they really are - so don't get your hopes up.

Actually, i think it started to help prevent (3, Insightful)

Unknown Poltroon (31628) | more than 11 years ago | (#5972534)

employee theft.
If the price is 1.00$, the person working the regster can just take the buck, or five, or whatever, and slide it into their pocket. If its .99, or 1.95, or 7.53, they gotta make change by opening the register.

Re:Instead... (3, Funny)

aborchers (471342) | more than 11 years ago | (#5972596)

So getting rid of marketeers would *also* simplify making change? What are we waiting for?!

Re:Instead... (1)

soccerisgod (585710) | more than 11 years ago | (#5972608)

I think, my dear friend, there is no aspect of life that would not get significantly easier without marketeers ;)

Re:Instead... (1)

fobbman (131816) | more than 11 years ago | (#5972562)

I thought about that, too. Thought it would be a great idea to get rid of pennies. Then two words hit me and it all fell apart: sales tax.

Re:Instead... (5, Informative)

jmv (93421) | more than 11 years ago | (#5972584)

In France (and probably other countries) most of the prices end in .00 and the taxes are already included (unlike Canada where I live). It's much simpler that way. If only there was a way to convince stores to do that in here...

Re:Instead... (1)

bigox (158657) | more than 11 years ago | (#5972597)

Plus, a one to two cent difference on very high volume items make a different to their bottom lines. Think gasoline.

4 coins? (1, Funny)

xchino (591175) | more than 11 years ago | (#5972469)

"There are mostly four kinds of coins in circulation in the U.S: 1 cent, 5 cents, 18 cents, and 25 cents"

Where is this 18 cent coin? Have I been living under a rock? Are my dimes now worth 18 cents?

18 cents? (-1, Redundant)

Whatsthiswhatsthis (466781) | more than 11 years ago | (#5972470)

"There are mostly four kinds of coins in circulation in the U.S: 1 cent, 5 cents, 18 cents, and 25 cents."

I swear, I turn my head for one minute and now we have 18-cent coins?

Can michael moderate for noncents?

Ah the new math. (2, Funny)

SphynxSR (584774) | more than 11 years ago | (#5972477)

I had 18 cents everytime I heard that.

The quarter is hard enough (5, Funny)

charlieo88 (658362) | more than 11 years ago | (#5972483)

I was at a conveinece store yesterday. The price came to $1.37. I tendered $2.12. The cashier's head almost exploded.

Re:The quarter is hard enough (1)

Nostrada (208820) | more than 11 years ago | (#5972580)

This is so funny. You get this reaction at Taco bells, MC D, or BK as well. They look at you as if you were asking for some carnal knowledge or worse.

Re:The quarter is hard enough (3, Funny)

LPetrazickis (557952) | more than 11 years ago | (#5972582)

As someone who used to work in a similar establishment, let me just say that I hated people like you.;)

And I like math.:P

87 cent Loony? (1, Funny)

JohnnySkidmarks (607274) | more than 11 years ago | (#5972484)

Here in Canada the only chance of our coinage being worth 87 cents is if the US keeps up it's foreign policy for another 6 months. (our dollar hasn't been this high in about 7 years)

I would pay 25 cents for an 18 cents coin! (0, Redundant)

AwesomeJT (525759) | more than 11 years ago | (#5972492)

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

Re:I would pay 25 cents for an 18 cents coin! (0)

Anonymous Coward | more than 11 years ago | (#5972558)

But it's not true, so there is no factual value!

back in my day... (1)

abe_is_fun (320753) | more than 11 years ago | (#5972493)

...to take the ferry costs a nickel. And in those days nickels had pictures of Bumble Bees on them. `Gimme five bees for a quarter' you'd say.

I'll be deep in the cold, cold ground before I recognize the eighteen cent coin.

REDUNDANT: 18-cents (0, Redundant)

p3d0 (42270) | more than 11 years ago | (#5972499)

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

When Mathmeticians Lose Touch with Reality (0, Flamebait)

fobbman (131816) | more than 11 years ago | (#5972500)

Sorry, but the average white-bread eating American does not have the mental capacity to use an 18 or 32 coin.

It's nice to know, however, that the University of Waterloo math department doesn't do drug testing of their employees.

No way! (1)

kavachameleon (637997) | more than 11 years ago | (#5972502)

There is no way that as a cashier, I could *ever* come up with change involving 18 cent coins. This is not because I am math-ignorant, it's just not easy. I mean, come on! There are really and literally people I work with that misfile names alphabetically. They spell "Customer" "Coustomer." 18 cents wouldnt work.

Obligatory Weak Joke:= (1)

big_gibbon (530793) | more than 11 years ago | (#5972503)

Obligatory weak joke: "Doctor doctor, I've turned into a coin!" "Well that makes a change!" Ho ho, and indeed, ho P

yeah right.... (1)

botzi (673768) | more than 11 years ago | (#5972504)

Shallit assumed that every amount of change between 0 and 99 cents is equally likely. Why do I feel like from there on it doesn't worth reading it??????????

Yeah, right... (5, Funny)

Frightened_Turtle (592418) | more than 11 years ago | (#5972507)

So- you have 7 18-cent coins, Susie gives you 13, and you give Bobbie 3. How many nickels must Daddy give you for your 18-cent coins...?

Then, you get on a train in Boston traveling east at 300 MPH. In 30 minutes, will you really care about how many 18-cent coins you're carrying?

Re:Yeah, right... (2, Funny)

d_lesage (199542) | more than 11 years ago | (#5972587)

If you get on a trin travelling *east* from *Boston*, it's going to take you a hell of a lot less than 30 minutes not to care. You're more likely to care about the lack of oxygen.

in other news ... (0)

Anonymous Coward | more than 11 years ago | (#5972511)

The Federal Treasury will be announcing new $30.00 bills to replace the old $27.00 bills ..

Science v. Common Sense (5, Interesting)

MilesParker (572840) | more than 11 years ago | (#5972519)

More proof of the ungoing schism between science and common sense.

Me, I'm on the side of science.

Actually it would take more time.... (1)

rxed (634882) | more than 11 years ago | (#5972521)

18 cents may give you less coins but it would take more time for a cashier to give you correct change.

I find this highly suspect... (1)

tundog (445786) | more than 11 years ago | (#5972531)


Wouldn't local sales tax and price distribution play a major role in usefule coin calculation? While the average may point to an 18 cent coin, the distribution plays a much more important role. Factor in the difference in region sales taxes and you end up with a coin that is not only based-10 friendly, but also fails to meet the intended results.

Then again, maybe I should RTFA. Then again, this is /.

More to transactions than number of coins. (3, Insightful)

Violet Null (452694) | more than 11 years ago | (#5972533)

You think it's bad enough when the cashier has to use the machine to figure out how much change to give, and in what denominations? You think it's bad when the little old lady in front of you in line starts counting, and then double-counting to make sure, the change she's going to hand over?

You give them a 29 cent piece and see how fast things get.

I'm willing to bet that most of the "coin cost" or whatever you want to call it comes from pennies, anyway -- if the dollar amounts are random, every 5 transactions are going to involve (0 + 1 + 2 + 3 + 4 = ) 10 pennies, or 2 pennies per transaction. Rounding prices to the nickel would be simpler, easier, and more efficient.

typical Computer Science logic (2, Insightful)

citroidSD (517889) | more than 11 years ago | (#5972536)

more efficient transaction costs?? Again the computer scientists are concentrating on the efficiency of the system, without any regard to the efficiency of the user. What is more important, handing back a smaller amount of change, or allowing for quicker mental computation of what coins to use in the transaction? For example when you are told something costs $3.48, it takes more time to calculate how to break up 48 cents into the available coin denominations, then it does to to actually exchange and identify the coins. The system is not what needs to be optimized, instead the user is what matters, and our mind work well in 10's and 5's.

Oh, that'll work well (4, Interesting)

Viogression (231351) | more than 11 years ago | (#5972537)

My mother went to the store to purchase something. The price on it was $20. It was also marked 25% off. It rang up as $18 instead of $15. My mother pointed this out, but the cashier would have none of it. "No, no, that sounds like 25% off."

How the hell can we expect these people to handle 18 cent pieces when they can't even figure out what 25% of 20 is?

what a waste of time, the real solution is simple. (0)

Anonymous Coward | more than 11 years ago | (#5972539)

The actual solution to eliminating time wasting change is this

instead of $9.99 plus tax, charge $10 plus tax, in Canada tax is 15%, so it would be $11.50, nice and even. Round up all those fuckin' $9.95, 14.95, $39.94, $199.95 and such prices UP, yes, UP, round them to the nearest 5 or 10. Simple.

What the fuck kinda mathematician doesn't consider the logic of the world before embarking on studying it?

Jesus tapdancing Christ (0)

Anonymous Coward | more than 11 years ago | (#5972540)

18 cents? Holy living fuck, I'm starting to think that all of these errors in Slashdot stories are purely intentional. How in the hell can you let something like that slip through? I can't even begin to imagine. Do people even *read* submissions before they get posted?

Why does my intuition says something else? (1)

ptaff (165113) | more than 11 years ago | (#5972541)

Using base 2, with 1 cent, 2 cents, 4 cents, 8 cents pieces, ..., $1.28 bills, ...

you actually can have any amount up to $10245.76 using a maximum of 20 pieces/bills.

On average you'd have 10 pieces/bills, which is not too bad.

To have 20 dollars bills and "round" amounts is irrelevant: taxes always cast the amount you have to pay into a float anyway.

Tax dollars at work (1)

batkid (448363) | more than 11 years ago | (#5972542)

So we are spending our hard earned dollars to fund a research on how to give change back.

They are making real progress in improving mandkind... maybe one day we'll get this magic coin that can represent everything under 10 cents...

Or, even better ... (2, Informative)

simong_oz (321118) | more than 11 years ago | (#5972544)

Do what Australia did a while back and round everything to the nearest 5c and get rid of 1c and 2c coins entirely (so now Australian coins are 5c, 10c, 20c, 50c, $1 and $2). I couldn't decide whether I liked it to start with, but after a little while you realise just how much shrapnel you carry around and have no intention of using except to empty it from your pocket/wallet at the end of every day. Every time I go to another country and have to again deal with 1/2 cent/euro cent/pence/etc I just appreciate this move even more.

express checkout (1)

w3weasel (656289) | more than 11 years ago | (#5972547)

so the pimple-faced cashier at my local taco bell will now spend 20 minutes staring blankly at the register rather than the 15 minutes he currently spends on this activity.
Efficiency is great but give me a hot gordita anyday

AHA!!! I knew it! (1)

Twilight1 (17879) | more than 11 years ago | (#5972548)

This is the real reason they killed off all the dime stores in the US! It was a conspiracy all along! Run away, run away!

-Twilight1

Canadiana (1)

Malicious (567158) | more than 11 years ago | (#5972551)

In Canada, it's Illegal to pay for any good or service, with more than 25 of any given denomination.
For example, my friend tried to pay his parking ticket with a giant glass jar of pennies. The Clerk took the pennies, kept them and informed my friend that his fine was still outstanding. If the Pennies had been rolled, it would be legal for him to pay up to 25 rolls. As such, he got screwed out of his pennies, and still had to pay the ticket.

Author is Canadian (1)

vondo (303621) | more than 11 years ago | (#5972555)

Do you think it's possible there is an ulterior motive of totally screwing up commerce in the United States behind this proposal?

Seriously, though, short of going to the Euro 1,2,5,10,... system we need a smaller 50 cent piece that actually gets used. And, of course, having sales tax already in the items and then priced to the nearest 5 cents would help. I spent 4 or 5 days in Paris before I ever needed or received a 1 or 2 cent euro coin.

It is our stupid pricing system (1)

gosand (234100) | more than 11 years ago | (#5972557)

Maybe the problem with making change is the dumb way we price and charge for things. I spent a week in Paris, and didn't see a penny until the last day. Maybe I just got lucky, but it seemed everything was priced so that you didn't get pennies back for change. I also liked the fact that the tip was always included in the price of a meal.

Why do we still have pennies anyway? Nobody likes them. They are trying to outlaw them in tollbooths here in Illinois, so even the state doesn't want them. The "leave a penny" containers always seem full where I shop. They are just an annoyance, IMO.

Good job HOMIE (1)

mofochickamo (658514) | more than 11 years ago | (#5972560)

There are mostly four kinds of coins in circulation in the U.S: 1 cent, 5 cents, 18 cents, and 25 cents

I only have one thing to say to this: PREVIEW!

Let me grab a calculator (1)

robbway (200983) | more than 11 years ago | (#5972563)

Despite the earnestness of the article and research, this should probably be under Laugh, It's Funny. People grab a calculator for 6 times 3. Imagine having to carry the one for all your transactions?

The fact that other countries with a decimal system of currency have different suggested value coins indicates the "efficient coin" is based on the current economy.

penny, nickel, dime, decoct, quarter,.... The kids are going to have a field-day with this one!

That may be true, but... (0)

Anonymous Coward | more than 11 years ago | (#5972565)

Here on planet earth, many of the clerks I deal with have trouble counting out change with the current denominations. If they have trouble counting by fives, how well do you thing they'll handle counting by 18 or 29.

Wrong Optimization (1)

Obsequious (28966) | more than 11 years ago | (#5972566)

This is a classic computer science problem: the guy optimized space over time.

He came up with a solution that presents the fewest coins -- that is, the most "compact" solution in space, where space is number of coins. However, this solution comes at the cost of computational complexity -- the time required to figure out the math.

It's an interesting notion, and worth considering, but in practice it's not viable. I value my TIME far more than I value the SPACE in my change purse. :)

Math? you want me to do math? (1)

Cade144 (553696) | more than 11 years ago | (#5972567)

While these demoniations may be more efficent for reducing the number of coins per transaction, I would think that they would increase the complexity of the math requuired to do the transaction, and the time to count the change back.

This would not necessairly increase the efficency of change transactions.


I would think the implementation of the "Two Penny Lottery" would reduce the amount of change needed just nicely.

Pennies would be removed from circulation, although for electronic transactions, everything would still be counted down to the nearest cent.
If the pack of gum I just bought comes to $0.88 (with tax) I would pay $0.90 and loose two cents. Things would even out because I would come out ahead by paying only $0.85 if it cost $0.87 .


That would reduce the number of coins less than a dollar in circulation to three.

All wrong... (0)

Anonymous Coward | more than 11 years ago | (#5972572)

This is the worst idea ever. Has this person ever been out of the math department?

A much better idea - round to the nearest 10 cents!

A $0.18 coin? (1)

Rude Turnip (49495) | more than 11 years ago | (#5972575)

Why, that's as queer as a $3 bill!

Musings on an 18 cent coin (1)

babbage (61057) | more than 11 years ago | (#5972578)

verification, n.
An optional method of compounding the errors of data entry: e.g., the situation where Jo(e) decides that the "8" that Fred(a) thought was a "3" is really a "5."

-- from _The Computer Contradictionary_, Stan Kelly-Bootle, 1995

Or in this case, that the 0 was an 8 -- repeatedly :-)

Someone stop this man! (1)

soccerisgod (585710) | more than 11 years ago | (#5972579)

1.37 cent??? Is this man completely fakakte?

People already got used to the euro and are calculating it's value in their old currency every time they have to handle prices. I've heard that certain elderly french people even convert the euro prices to old france, a currency that expired decades ago. If you add to that such superodd values, you can expect total chaos throughout of europe - except perhaps for germany, where the exchange rate between DM and Euro is almost 2:1 ;)

Can't change peoples' thinking (1)

cruppel (603595) | more than 11 years ago | (#5972583)

There's no way you're going to teach entire countries to just op thinking in terms of 1, 5, 10, 25 and start thinking about 83 cent coins, or 1.37 dollar bills... The effiency achieved would most likely take years to just balance the inconvenience and trouble caused by shifting the way money has worked in the past. It wasn't too many years ago that I worked at a grocery store, and I can still tell you all the finer points of a change drawer (i.e. one of each coin makes 41 cents). Too many people rely on the situation not changing.

Bad assumption? (0)

Anonymous Coward | more than 11 years ago | (#5972585)

"Shallit assumed that every amount of change between 0 and 99 cents is equally likely."

Most things I buy are xxx.99 or xx.29 or xxx.50 or xxx.00 etc. so (extrapolating to the general public) I would say the average change amount required for change-requiring transactions is *not* an even distribution.

The logic is flawed (1)

friendofafriend (602350) | more than 11 years ago | (#5972592)

The article says he assumed all amounts of change between 1 and 99 cents have the same probability. I would argue this is not true - how many things are $X.99 plus tax, or similar?

In Theory vs. In Practice (0)

Anonymous Coward | more than 11 years ago | (#5972593)

This looks like yet another "It works on paper" idea. It should be a requirement for these guys to leave the lab once in a while.

The difference between theory and practice is: in theory, there should be no difference between theory and practice. But in practice, there is a big difference.

Anonymous Kev
proudly posting as AC since 1997

hey buddIE, can you spare a .com? (-1, Offtopic)

Anonymous Coward | more than 11 years ago | (#5972595)

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Minimize coins in pocket (3, Interesting)

f97tosc (578893) | more than 11 years ago | (#5972598)

It seems like the objective here was to minimize coin exchange. Ususally I try to minimize the number of coins in my pocket.

If something costs 77c I give them 1.02 - and get a quarter back. In the US, the tellers stare at me blankly, but then dutifylly enter the amount I give them - and then smile in amazement at the simplicity of the exchange.

In Japan, it is almost the other way around. The tellers come up with the most creative combinations that minimize my number of coins (and maximize theirs - this is in both of our interest).

Tor

what about... (1)

mirko (198274) | more than 11 years ago | (#5972599)

what about asking these fscking marketers to drop their psychological price philosophy and sell things for 1$ instead of 99 cents ???

Submitting Story (1)

Malicious (567158) | more than 11 years ago | (#5972601)

EDIT!

If there's any mistakes, you should have used the preview button!

Apparently, we have different rules than they.

This is why Human Interface Design is important (3, Insightful)

Bingo Foo (179380) | more than 11 years ago | (#5972605)

  1. Some egghead thinks "optimal" means "fewest coins returned in change, on average."
  2. He recommends introducing 18 and 83 cent coins.
  3. The people who actually use coins laugh at this idiocy.
Sheesh, "optimal" coinage denominations are those that make using coins easiest. That means quick mental calculations of change, manipulating them with your fingers, and passing them back and forth.

The ivory tower academics are certainly earning their reputation for foolishness.

Six finger cashiers (1)

BreadMan (178060) | more than 11 years ago | (#5972606)

Love the idea.

Just eliminate pennies (1)

DustMagnet (453493) | more than 11 years ago | (#5972607)

From my rough calculations, we could go from 4.70 coins per transaction, to 2.70 coins by getting rid of those worthless pennies. That is certainly a lot easier than dividing by 18 and 29.

My math: 4.70 - (0+1+2+3+4)/5 = 2.70 (Probably close but wrong)

Better idea (1)

kinnell (607819) | more than 11 years ago | (#5972612)

Get rid of any coins which are too small to actually buy anything with. That way you don't wind up having to periodically pick through your small change to get rid of those 1 and 2 cent pieces which you only have because everythings priced at xx.99 or xx.98.
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