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Anu wrote: "We use the decimal system because there are ten fingers on our hands."
This might be one of the reasons. However, there are mathematical reasons that made people use it: The decimal system is much more practical than the hexagesimal system the Babylonians used or the duodecimal one. At least for human beings - computers are much more comfortable with either the binary system or the ...dunno... 0-to-F system (FF being 255 in "real numbers" ;-)
We can add, multiply... numbers in a most elegant and easy way using the decimal system, much easier than in any other system. Try and calculate 7% of 20 Euros or Dollars using the decimal system and then do the same using the decimal system or the binary system :-)
However, considering the poor performance of way too many young people when it comes to most basic calculations as the one mentioned above none of the system seems to be working. How come? :confused:
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Carpal Tunnel
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Decimal arithmetic is comfortable for us because we're used to it. If you had done your times tables in duodecimal or hexadecimal you'd probably find the decimal system confusing.
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Hi Carsten - welcome. I think Carsten's got a point myself, Faldo - after all, the ease of moving the decimal point outweighs all the rote learning I did as a kid learning the old British duodecimal currency system, may it rest forever in a pit of half-congealed school custard. edit: sp 
Last edited by maverick; 03/13/06 04:10 PM.
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What was that money called, mav? A shilling was one part of it, right? Here's a link to a Dozenal Society: reminds me of Save the Apostrophe Also--is our duodenal system so called due to some relationhip to the number 12?
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Our crazy old currency, complete with farthings, ha’ppennies, pennies, tuppences, thre’penny bits, tanners, shillings or bobs, two-bobs, half-a-crown, crown, pound, and guinea was generally known as ‘the duodecimal system’ ~ but only once we had started discussing then implementing the alternative…  ¼ penny = farthing (obsolete from waybackwhen) ½ penny = “ha’pence” or “ha’penny” 1 penny = 1d 2 pennies = “tuppence” or “tuppeny piece” 3 pennies = “thre’penny bit” or “thre’pence” 6 pennies = “sixpence” or “tanner” 12 pence = 1 shilling (1/-) ~ also known as “a bob” 24 pence = 2 shillings (2/-) ~ in single coin, known as “two-bob” 30 pence = 2 Shillings 6 pence (2/6) ~ also known as “two-and-six” or “half a crown” 60 pence = 5 shillings = crown (rarely in circulation) 120 pence = 10 shillings (10/-) ~ also known as “ten-bob note” 240 pence = 20 shillings (20/-)* = 1 pound (£1/-/-)* ~ also know as “a quid” 252 pence = 21 shillings = 1 guinea (ancient terminology beloved of lawyers) *I can’t actually remember this notation accurately. Can you see why it was so indigestible? And speaking of which: Duodenum
[med.L. (so called from its length, = duodénum digitorum space of twelve digits, inches, or finger's breadths), f. duodéni twelve each (see duodene). Used in Fr. in 1514 (Hatz.-Darm.).]© OED v2
Last edited by maverick; 03/13/06 04:42 PM.
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Faldage is right. It's not the decimal point being part of the ten based system, it's the system you are used to.
Consider a nonal system:
1
2
3
4
5
6
7
8
10.
If you move the nonal point one over to the left, you get 100. But that is actually nine nines, or 81 decimal. In nonal, it's 100 (and you can call it a hundred if you want to, since that's just a name for a number that's your base plus one. One of nice things about a nonal system is you can take a square root of the base and have an even number: 3 x 3 = 10 (nine decimal).
It really is just that the decimal system is what you are used to. And you can use any base you want to. If it's higher than 10 you just have to come up with new symbols (or recycle familiar ones) to represent the numbers from 1 to your new 10. Don't think of your 10 as ten in decimal, (you can call it that if you want to); you have to train yourself to think of it in terms of your base.
For example, if you use base 16, the convention is to use 1 through 9, then A, B, C, D, E, and F to represent what we think of as 10 through 15 in base ten. 10 is not ten, it's F plus 1. And 100 is 10 times 10, but if you convert it it comes out to 256 in our decimal system. Makes for compactness when dealing with large numbers, and works really well on the computer.
The one I'd like to see is a trinary system for computers. Binary of course is 1s and 0s. Ons and Offs. But in a trinary system, you would have plus charge, minus charge, and neutral, at least the way I put it together in my mind. In fact, though I've thought of it before, this may well be the first time I've actually told anyone about it. It just seems to me that you can make computations a LOT faster than you can in binary, since information would flow 50 percent faster. Though not being a computer whiz I'll admit that's speculation on my part.
It would be 1, 2, 10, 11, 12, 20, etc. 10 would be our decimal 3, 20 our decimal 6, and 100 our decimal 9.
TEd
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Quote:
Also--is our duodenal system so called due to some relationship to the number 12?
Did we not read our A.W.A.D. today??
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>you can take a square root of the base and have an even number: 3 x 3 = 10 (nine decimal).
a less confusing way to say that is that the square root of the base (10) is a whole number (3), 3 being odd. : )
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> It really is just that the decimal system is what you are used to.
yeahright. So what's 17 and a half percent of 15 guineas 18 shillings and sevenpence three-farthings?
Last edited by maverick; 03/13/06 05:21 PM.
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