Re: Bases, was Re: Stirling engine queries

2004-03-06 Thread Robert Seeberger

- Original Message - 
From: David Hobby [EMAIL PROTECTED]
To: Killer Bs Discussion [EMAIL PROTECTED]
Sent: Friday, March 05, 2004 11:49 PM
Subject: Re: Bases, was Re: Stirling engine queries


 Robert Seeberger wrote:
 ...
   I'd say that this stuff gets pretty fuzzy.  One could argue
   that 5 is more important than 11 and 13.  On the other hand, one
   could say that ending tests are better than sum of digits tests,
   and conclude that 12 is superior since it replaces sum of digits
   tests for 3,9,... with ending tests.  Is this the kind of thing
   you were thinking about?
  
   ---David
 
  Who needs whole number divisibility when you have fractions and
can
  work decimals?
  You would have to do these things no matter what the base you use,
in
  the real world.
  Getting people to change bases would be whole magnitudes of
difficulty
  greater than getting them to go metric.
  G
 
  xponent
  Numbers game Maru
  rob

 Of course we could use base 7 or whatever, and get by
 almost as well.  And I agree that getting anyone to change would
 be hopeless.  I sometimes teach a math course for future elementary
 school teachers, and wind up spending a week teaching them the
 metric system, for college credit (!!).  At the end of it, half
 of them say things like a cubic meter is a liter, which weighs
 a gram.  (So be prepared to teach your own children math...)
 Rob, the point of this discussion was to explain why
 we picked the base we did.

I understand, but what I was saying is that it doesn't really make all
that much a difference. There are just too many cases where you would
still be using fractions and decimals, so a different base doesn't
simplify things in the long run.
Base 12 might be helpful when doing math in your head and it might be
more intuitive in the most simple situations, but surely there would
have to be some other overiding reason to use another base (other than
 the arbitrary numbers of digits, knuckles, and limbs), such as in the
CS uses of Binary, Octal, And Hexadecimal.


 Having ten fingers is obviously a
 key factor, but there are examples of cultures that used base
 20 or 60, so it's not exactly the only one.  I imagine that
 we would use base 12 if we had 6 fingers.  But suppose we had
 3 hands with 7 fingers each.  Would we really use base 21?


WellI agree.but the point I was making implies that it doesn't
really matter which base one uses in the long run. A value is a value
no matter how it is expressed. And that's really what is being
discussed isn't it? How values are expressed and if there are better
ways to do this? (I'm thinking that calculation is a straightforward
mechanical process in any base.)

Am I wrong in thinking this?

xponent
123456789ABCDEF Maru
rob


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Re: Bases, was Re: Stirling engine queries

2004-03-06 Thread David Hobby

 I understand, but what I was saying is that it doesn't really make all
 that much a difference. There are just too many cases where you would
 still be using fractions and decimals, so a different base doesn't
 simplify things in the long run.
 Base 12 might be helpful when doing math in your head and it might be
 more intuitive in the most simple situations, but surely there would
 have to be some other overiding reason to use another base (other than
  the arbitrary numbers of digits, knuckles, and limbs), such as in the
 CS uses of Binary, Octal, And Hexadecimal.
 
  Having ten fingers is obviously a
  key factor, but there are examples of cultures that used base
  20 or 60, so it's not exactly the only one.  I imagine that
  we would use base 12 if we had 6 fingers.  But suppose we had
  3 hands with 7 fingers each.  Would we really use base 21?
 
 
 WellI agree.but the point I was making implies that it doesn't
 really matter which base one uses in the long run. A value is a value
 no matter how it is expressed. And that's really what is being
 discussed isn't it? How values are expressed and if there are better
 ways to do this? (I'm thinking that calculation is a straightforward
 mechanical process in any base.)
 
 Am I wrong in thinking this?
 
 xponent

No, you're right.  To first order, any base would work.
But there are some subtle reasons for prefering some bases over
others.  Take -pi as a base, for instance.  Then pi^2 - 3*pi 
+ 2*1 - 2*pi^(-1) + 2*pi^(-2) = 2.0108..., so we have that two
is 132.22... in base -pi.  If you pick the wrong base, all the
numbers you care about will be infinite decimals.  : )

---David
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Re: Bases, was Re: Stirling engine queries

2004-03-06 Thread Robert Seeberger

- Original Message - 
From: David Hobby [EMAIL PROTECTED]
To: Killer Bs Discussion [EMAIL PROTECTED]
Sent: Saturday, March 06, 2004 2:22 PM
Subject: Re: Bases, was Re: Stirling engine queries


  Am I wrong in thinking this?
 

 No, you're right.  To first order, any base would work.
 But there are some subtle reasons for prefering some bases over
 others.  Take -pi as a base, for instance.  Then pi^2 - 3*pi
 + 2*1 - 2*pi^(-1) + 2*pi^(-2) = 2.0108..., so we have that two
 is 132.22... in base -pi.  If you pick the wrong base, all the
 numbers you care about will be infinite decimals.  : )


Which is the reason we strive for whole number intuitiveness.


xponent
Base Planks Constant Maru
rob


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Re: Bases, was Re: Stirling engine queries

2004-03-05 Thread Ray Ludenia
Alberto Monteiro wrote:

 Alberto Monteiro who spends his time in the traffic looking at
 the numbers of the cars and dividing them by 11.

I spend my time making words from the three letters on the plates we have
here. Keeps me amused for a while. Bonus points for naughty words. Did I say
I hate traffic?? No! Well, I do.

Regards, Ray.

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Re: Bases, was Re: Stirling engine queries

2004-03-05 Thread David Hobby
Robert Seeberger wrote:
...
  I'd say that this stuff gets pretty fuzzy.  One could argue
  that 5 is more important than 11 and 13.  On the other hand, one
  could say that ending tests are better than sum of digits tests,
  and conclude that 12 is superior since it replaces sum of digits
  tests for 3,9,... with ending tests.  Is this the kind of thing
  you were thinking about?
 
  ---David
 
 Who needs whole number divisibility when you have fractions and can
 work decimals?
 You would have to do these things no matter what the base you use, in
 the real world.
 Getting people to change bases would be whole magnitudes of difficulty
 greater than getting them to go metric.
 G
 
 xponent
 Numbers game Maru
 rob

Of course we could use base 7 or whatever, and get by
almost as well.  And I agree that getting anyone to change would
be hopeless.  I sometimes teach a math course for future elementary
school teachers, and wind up spending a week teaching them the 
metric system, for college credit (!!).  At the end of it, half 
of them say things like a cubic meter is a liter, which weighs
a gram.  (So be prepared to teach your own children math...)
Rob, the point of this discussion was to explain why
we picked the base we did.  Having ten fingers is obviously a
key factor, but there are examples of cultures that used base
20 or 60, so it's not exactly the only one.  I imagine that 
we would use base 12 if we had 6 fingers.  But suppose we had
3 hands with 7 fingers each.  Would we really use base 21?

---David

Four score and seven
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Re: Bases, was Re: Stirling engine queries

2004-03-05 Thread David Hobby
Julia Thompson wrote:
 
 David Hobby wrote:
...
  So base 12 is not bad, it gives nice tests for 2,4,8,...
  for 3,9,..., for 11 since 12 = 11 + 1 and it gives a poor test for
  13 since 12^2 = 11*13 + 1.  The situation for 5 and for 7 seems to
  be even worse.
  Contrast this with base 10, which gives a good test for 5
  but has a worse test for 11 and none for 13.
  I'd say that this stuff gets pretty fuzzy.  One could argue
  that 5 is more important than 11 and 13.  On the other hand, one
  could say that ending tests are better than sum of digits tests,
  and conclude that 12 is superior since it replaces sum of digits
  tests for 3,9,... with ending tests.  Is this the kind of thing
  you were thinking about?
 
 The sum of digits test for 3 only works because it's the square root of
 9.

As Alberto(?) pointed out, it works for all factors of 9.
Well, that's a poor example, but you get the idea.


 Base 12 would give better tests for more numbers.  And a sum of digits
 test would work for 11 there.
 
 Julia

As would an alternating sum of digits test for 13, similar to 
the base 10 test for divisibility by 11.  (Here's a good background
link:  http://www.jimloy.com/number/divis.htm  )
We could also look at the problem in terms of which common
fractions are represented by terminating decimals or by those with 
simple patterns of repetition.  This is essentially the same thing 
as considering divisibility tests, and may seem more sensible.

For example, in base 10 we have ending tests for divisibility
by 2,4,5,8 and so on, and these are the denominators of the
fractions that have terminating decimals.  (1/2 = .5, 1/4 = .25, etc)
We have sum of digits tests for 3 and 9, these correspond to the
simple patterns:  1/3 = .3... and 1/9 = .11...
Finally, 11 and 7 have divisibility tests which are poor and 
awful respectively.  Now look at the decimal expansions of their
reciprocals:  1/11 = .0909090909... and 1/7 = .142857142857...

---David
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Re: Bases, was Re: Stirling engine queries

2004-03-05 Thread Steve Sloan II
David Hobby wrote:

 At the end of it, half of them say things like a cubic
 meter is a liter, which weighs a gram.
While we're already talking about changing our number systems,
maybe we should change metric to make that true, because those
definitions make a *lot* more sense than the real ones. :-)
Honestly, why the heck is a liter defined as a cubic
*decimeter*? Granted, a cubic meter would make an awfully big
base unit of volume, but it wouldn't really be any more awkward
than a gram, which is too *small* to be really useful in everyday
life. If the metric units weren't so awkwardly sized, there would
be no need for two different sets of metric base units, cgs (cm,
grams, seconds) and SI (meters, kilograms, seconds). Each set has
to fudge one of the units by a factor of 1000 to get it to play
well together with the other unit.
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Re: Bases, was Re: Stirling engine queries

2004-03-05 Thread David Hobby
Alberto Monteiro wrote:
 
 David Hobby wrote:
 
  However, a base 12 counting system would have been much better;
 
  No, it wouldn't
 
Well, a little better.
 
 A little worse.
 
  Depending how you count, you can
  argue that 12 has more factors than 10.  This must be worth
  something, since I don't hear anyone pushing for prime bases such
  as 11.  Agreed, it's not a big deal.  It might be more to make a
  number base feel comfortable than a great aid in calculations.
 
 The problem with base 12 is that it has _2_ twice and _3_ once
 when you factor it, so that the practical man rules to check
 if a number is divisible by another would get a higher degree
 of confusion. Base 6 would be a much better choice than base 12.

I'm not sure what you mean.  I don't find the divisibility tests
confusing.  Some are simpler than others, yes.  And we may well
disagree on how to compare degrees of simplicity.

 I don't see many advantages in base 6 over base 10:
 the only one that comes to my mind is that base 10 has simple
 rules to check if a number is divisible by 2, 5, 3, 9 and 11;

I think the rules for 4,6 and 8 are also simple.  (Again, here's
a link for background:  http://www.jimloy.com/number/divis.htm  )

 with
 base 6, there would be simple rules for 2, 3, 5 and 7; maybe
 losing 11 and gaining 7 could count as a minor improvement.

I would say that there are also simple rules for 4, 8, 9 and 10
when working base 6.  (This is making base 6 look good.  But 
there should be a way to lift divisibility rules from base 6 to
base 12 (=2*6), at the price of adding some complexity.)

 OTOH, base 12 would have simple rules for 2, 3, 4, 6, 11 and 13,
 and since the base-10 rules for 4 and 6 are one bit less simple
 than the rules for 4 and 6 in base-12, we would _lose_ the
 rules for 5 and gain the rules for 13 - which is a bad trade.

Again, I would count more rules as simple.  I see that you are
counting the base 10 rule for 4 as one bit less simple than 
the base 10 rule for 2.  Would the base 10 rule for divisibility
by 8 be two bits less simple?  This is fuzzy, as I said.  I
would count the base 10 rule for 3 as much less simple than the
base 10 rule for 8, even.  I guess it depends on what size 
numbers one is expecting to use the divisibility tests on--
I'm imagining large numbers as input.

---David

The divisibility by 3 test runs in linear time, Maru.
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Re: Bases, was Re: Stirling engine queries

2004-03-04 Thread David Hobby

  Well, a little better.  Depending how you count, you can
  argue that 12 has more factors than 10.  This must be worth
  something, since I don't hear anyone pushing for prime bases such
  as 11.  Agreed, it's not a big deal.  It might be more to make a
  number base feel comfortable than a great aid in calculations.
 
 Base 10 has a minor advantage in divisibility tests that I don't think
 you get with any other possible base between 5 and 17.  And unlike 5 and
 17, it's not prime.
 
 Julia

There are two kinds of divisibility tests.  They aren't
usually given names, but let's call them ending tests and 
sum of digits tests.  Working base 10, there are ending
tests for 2,4,8,... and 5,25,... as well as for their products.
(Let's ignore combined tests for products such as 6, since those
can always be created.)
In base 10, there are nice sum of digits tests for 3 and 9,
and a poor one for 11.  (There's a really messy one for divisibility
by 7 as well, illustrating that it is always possible to produce
a poor test.)  The tests for 3 and 9 are based on the fact that
10 = 9 + 1, and the test for 11 uses that 100 = 9*11 + 1.
So base 12 is not bad, it gives nice tests for 2,4,8,...
for 3,9,..., for 11 since 12 = 11 + 1 and it gives a poor test for 
13 since 12^2 = 11*13 + 1.  The situation for 5 and for 7 seems to
be even worse.
Contrast this with base 10, which gives a good test for 5
but has a worse test for 11 and none for 13.
I'd say that this stuff gets pretty fuzzy.  One could argue
that 5 is more important than 11 and 13.  On the other hand, one
could say that ending tests are better than sum of digits tests,
and conclude that 12 is superior since it replaces sum of digits
tests for 3,9,... with ending tests.  Is this the kind of thing
you were thinking about?

---David
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Re: Bases, was Re: Stirling engine queries

2004-03-04 Thread Alberto Monteiro
David Hobby wrote:

 However, a base 12 counting system would have been much better;

 No, it wouldn't

   Well, a little better.  

A little worse.

 Depending how you count, you can
 argue that 12 has more factors than 10.  This must be worth
 something, since I don't hear anyone pushing for prime bases such
 as 11.  Agreed, it's not a big deal.  It might be more to make a
 number base feel comfortable than a great aid in calculations.

The problem with base 12 is that it has _2_ twice and _3_ once
when you factor it, so that the practical man rules to check
if a number is divisible by another would get a higher degree
of confusion. Base 6 would be a much better choice than base 12.

I don't see many advantages in base 6 over base 10: 
the only one that comes to my mind is that base 10 has simple
rules to check if a number is divisible by 2, 5, 3, 9 and 11; with
base 6, there would be simple rules for 2, 3, 5 and 7; maybe
losing 11 and gaining 7 could count as a minor improvement.

OTOH, base 12 would have simple rules for 2, 3, 4, 6, 11 and 13,
and since the base-10 rules for 4 and 6 are one bit less simple
than the rules for 4 and 6 in base-12, we would _lose_ the
rules for 5 and gain the rules for 13 - which is a bad trade.

Alberto Monteiro who spends his time in the traffic looking at
the numbers of the cars and dividing them by 11.

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Re: Bases, was Re: Stirling engine queries

2004-03-04 Thread Bryon Daly
From: David Hobby [EMAIL PROTECTED]
There are two kinds of divisibility tests.  They aren't
usually given names, but let's call them ending tests and
sum of digits tests.  Working base 10, there are ending
tests for 2,4,8,... and 5,25,... as well as for their products.
(Let's ignore combined tests for products such as 6, since those
can always be created.)
In base 10, there are nice sum of digits tests for 3 and 9,
and a poor one for 11.  (There's a really messy one for divisibility
by 7 as well, illustrating that it is always possible to produce
a poor test.)  The tests for 3 and 9 are based on the fact that
10 = 9 + 1, and the test for 11 uses that 100 = 9*11 + 1.
What are the divisibility tests for 7 and 11?

-bryon

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Re: Bases, was Re: Stirling engine queries

2004-03-04 Thread Julia Thompson
David Hobby wrote:
 
   Well, a little better.  Depending how you count, you can
   argue that 12 has more factors than 10.  This must be worth
   something, since I don't hear anyone pushing for prime bases such
   as 11.  Agreed, it's not a big deal.  It might be more to make a
   number base feel comfortable than a great aid in calculations.
 
  Base 10 has a minor advantage in divisibility tests that I don't think
  you get with any other possible base between 5 and 17.  And unlike 5 and
  17, it's not prime.
 
  Julia
 
 There are two kinds of divisibility tests.  They aren't
 usually given names, but let's call them ending tests and
 sum of digits tests.  Working base 10, there are ending
 tests for 2,4,8,... and 5,25,... as well as for their products.
 (Let's ignore combined tests for products such as 6, since those
 can always be created.)
 In base 10, there are nice sum of digits tests for 3 and 9,
 and a poor one for 11.  (There's a really messy one for divisibility
 by 7 as well, illustrating that it is always possible to produce
 a poor test.)  The tests for 3 and 9 are based on the fact that
 10 = 9 + 1, and the test for 11 uses that 100 = 9*11 + 1.
 So base 12 is not bad, it gives nice tests for 2,4,8,...
 for 3,9,..., for 11 since 12 = 11 + 1 and it gives a poor test for
 13 since 12^2 = 11*13 + 1.  The situation for 5 and for 7 seems to
 be even worse.
 Contrast this with base 10, which gives a good test for 5
 but has a worse test for 11 and none for 13.
 I'd say that this stuff gets pretty fuzzy.  One could argue
 that 5 is more important than 11 and 13.  On the other hand, one
 could say that ending tests are better than sum of digits tests,
 and conclude that 12 is superior since it replaces sum of digits
 tests for 3,9,... with ending tests.  Is this the kind of thing
 you were thinking about?

The sum of digits test for 3 only works because it's the square root of
9.

A sum of digits test would work for 2 and 4 in base 5.

A sum of digits test would work for 4 and 16 in base 17.

A sum of digits test would work for 5 and 25 in base 26.

Etc.

Base 12 would give better tests for more numbers.  And a sum of digits
test would work for 11 there.

Julia
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Re: Bases, was Re: Stirling engine queries

2004-03-04 Thread Robert J. Chassell
Julia Thompson [EMAIL PROTECTED] wrote

Base 10 has a minor advantage in divisibility tests that I don't
think you get with any other possible base between 5 and 17.  And
unlike 5 and 17, it's not prime.

What are the tests and the advantage?  I don't know anything about
this.  Perhaps it will reconcile me to base 10!

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Re: Bases, was Re: Stirling engine queries

2004-03-04 Thread Robert J. Chassell
... but can someone please count to 12 using the tips and top
knuckels of one hand, 'cause i only get 10. 

I count 12:

Looking at my left hand, palm towards my eyes, with my fingers curled
over, I see the four tips of my fingers and four of the knuckles
closest to my finger tips and four more which are the knuckles second
closest to my finger tips.

I can either divide that 12 into either 

  * three sets of four:  
tips, first set of knuckles, second set of knuckles,

each a set of four in three rows; or into

  * four sets of three:  
for each of four fingers, the tip, first, and second knuckle,

each finger having three obvious and visible places on it.

-- 
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Re: Bases, was Re: Stirling engine queries

2004-03-04 Thread Robert J. Chassell
Alberto Monteiro [EMAIL PROTECTED] wrote

The problem with base 12 is that it has _2_ twice and _3_ once
when you factor it, so that the practical man rules to check if
a number is divisible by another would get a higher degree of
confusion. 

Ah, I see your point.  However, I don't use those rules.  I learned
them many years ago, but don't remember them.

You raise an interesting point.  My question is whether the
application of those rules provides enough of a issue to have made
much of a difference these last 800 (base 10) years?

Base 6 would be a much better choice than base 12.

No, it would not, since 6 is not readily divisible by 4.  If you want
to make halves, thirds, and quarters easy, then 12 is the minimum.

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Re: Bases, was Re: Stirling engine queries

2004-03-04 Thread Nick Lidster


- Original Message - 
From: Robert J. Chassell [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Thursday, March 04, 2004 6:38 PM
Subject: Re: Bases, was Re: Stirling engine queries


 ... but can someone please count to 12 using the tips and top
 knuckels of one hand, 'cause i only get 10.

 I count 12:

 Looking at my left hand, palm towards my eyes, with my fingers curled
 over, I see the four tips of my fingers and four of the knuckles
 closest to my finger tips and four more which are the knuckles second
 closest to my finger tips.

 I can either divide that 12 into either

   * three sets of four:
 tips, first set of knuckles, second set of knuckles,

 each a set of four in three rows; or into

   * four sets of three:
 for each of four fingers, the tip, first, and second knuckle,

 each finger having three obvious and visible places on it.

 -- 
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 http://www.rattlesnake.com  GnuPG Key ID: 004B4AC8
 http://www.teak.cc [EMAIL PROTECTED]
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ill repost as you have missed my count, and how we were to make the count
using your provided rules.

( Also, if you look at the tips of your fingers and those knuckles
 closest to the tips, you will see 12 of them on one hand -- so it is

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yeh im probley stupid or forgot how to count.. but can someone please
count to 12 using the tips and top knuckels of one hand,  'cause i only get
10. I can see how one can do it, exclude teh thumb and the base knuckles,
use the tips and the top 2 knuckles of each finger, again rembering to
exclude the thumb. So as far as my base 10 counting skills go, it is
impossible to get 12 using 5 fingers, and 2 points of refrence.

Nick I cant count Lidster)

as you can see you stipulated that you were to use the tips of your fingers,
and the closest knucle to the tip, not all of the knuckles minus the base
knuckle as I stated in my rebuttle.



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26 May 2003

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Re: Bases, was Re: Stirling engine queries

2004-03-04 Thread Robert Seeberger

- Original Message - 
From: David Hobby [EMAIL PROTECTED]
To: Killer Bs Discussion [EMAIL PROTECTED]
Sent: Thursday, March 04, 2004 7:38 AM
Subject: Re: Bases, was Re: Stirling engine queries



   Well, a little better.  Depending how you count, you can
   argue that 12 has more factors than 10.  This must be worth
   something, since I don't hear anyone pushing for prime bases
such
   as 11.  Agreed, it's not a big deal.  It might be more to make a
   number base feel comfortable than a great aid in calculations.
 
  Base 10 has a minor advantage in divisibility tests that I don't
think
  you get with any other possible base between 5 and 17.  And unlike
5 and
  17, it's not prime.
 
  Julia

 There are two kinds of divisibility tests.  They aren't
 usually given names, but let's call them ending tests and
 sum of digits tests.  Working base 10, there are ending
 tests for 2,4,8,... and 5,25,... as well as for their products.
 (Let's ignore combined tests for products such as 6, since those
 can always be created.)
 In base 10, there are nice sum of digits tests for 3 and 9,
 and a poor one for 11.  (There's a really messy one for divisibility
 by 7 as well, illustrating that it is always possible to produce
 a poor test.)  The tests for 3 and 9 are based on the fact that
 10 = 9 + 1, and the test for 11 uses that 100 = 9*11 + 1.
 So base 12 is not bad, it gives nice tests for 2,4,8,...
 for 3,9,..., for 11 since 12 = 11 + 1 and it gives a poor test for
 13 since 12^2 = 11*13 + 1.  The situation for 5 and for 7 seems to
 be even worse.
 Contrast this with base 10, which gives a good test for 5
 but has a worse test for 11 and none for 13.
 I'd say that this stuff gets pretty fuzzy.  One could argue
 that 5 is more important than 11 and 13.  On the other hand, one
 could say that ending tests are better than sum of digits tests,
 and conclude that 12 is superior since it replaces sum of digits
 tests for 3,9,... with ending tests.  Is this the kind of thing
 you were thinking about?

 ---David

Who needs whole number divisibility when you have fractions and can
work decimals?
You would have to do these things no matter what the base you use, in
the real world.
Getting people to change bases would be whole magnitudes of difficulty
greater than getting them to go metric.
G


xponent
Numbers game Maru
rob


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Re: Bases, was Re: Stirling engine queries

2004-03-04 Thread Julia Thompson
Robert J. Chassell wrote:
 
 Julia Thompson [EMAIL PROTECTED] wrote
 
 Base 10 has a minor advantage in divisibility tests that I don't
 think you get with any other possible base between 5 and 17.  And
 unlike 5 and 17, it's not prime.
 
 What are the tests and the advantage?  I don't know anything about
 this.  Perhaps it will reconcile me to base 10!

In base N, to check to see if a number is divisible by N-1, just add the
digits, and if their sum is divisible by N-1, the number itself is.  So
in base 10, if the sum of the digits of a number add up to 9 or 18 or
27, etc., the number is divisible by 9.

If N-1 is a square, a similar divisibility test will work on sqrt(N-1). 
So if the sum of digits of a number in base 10 is divisible by 3, the
number itself is divisible by 3.

If you like having that nifty little extra divisibility test, your base
must be N^2+1 for some N.  So 5, 10 and 17 all work as bases with that
feature.

Base 12 has easier divisibility tests for more numbers, though.

Julia
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Bases, was Re: Stirling engine queries

2004-03-03 Thread David Hobby
Alberto Monteiro wrote:
 
 Robert J. Chassell wrote:
 
  However, a base 12 counting system would have been much better;
 
 No, it wouldn't
 
 Alberto Monteiro

Well, a little better.  Depending how you count, you can
argue that 12 has more factors than 10.  This must be worth 
something, since I don't hear anyone pushing for prime bases such
as 11.  Agreed, it's not a big deal.  It might be more to make a
number base feel comfortable than a great aid in calculations.

---David

All your base--no, forget I said that!
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Re: Bases, was Re: Stirling engine queries

2004-03-03 Thread Julia Thompson
David Hobby wrote:
 
 Alberto Monteiro wrote:
 
  Robert J. Chassell wrote:
  
   However, a base 12 counting system would have been much better;
  
  No, it wouldn't
 
  Alberto Monteiro
 
 Well, a little better.  Depending how you count, you can
 argue that 12 has more factors than 10.  This must be worth
 something, since I don't hear anyone pushing for prime bases such
 as 11.  Agreed, it's not a big deal.  It might be more to make a
 number base feel comfortable than a great aid in calculations.

Base 10 has a minor advantage in divisibility tests that I don't think
you get with any other possible base between 5 and 17.  And unlike 5 and
17, it's not prime.

Julia
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Re: Bases, was Re: Stirling engine queries

2004-03-03 Thread The Fool
 From: Julia Thompson [EMAIL PROTECTED]
 
 David Hobby wrote:
  
  Alberto Monteiro wrote:
  
   Robert J. Chassell wrote:
   
However, a base 12 counting system would have been much better;
   
   No, it wouldn't
  
   Alberto Monteiro
  
  Well, a little better.  Depending how you count, you can
  argue that 12 has more factors than 10.  This must be worth
  something, since I don't hear anyone pushing for prime bases such
  as 11.  Agreed, it's not a big deal.  It might be more to make a
  number base feel comfortable than a great aid in calculations.
 
 Base 10 has a minor advantage in divisibility tests that I don't think
 you get with any other possible base between 5 and 17.  And unlike 5
and
 17, it's not prime.

I endorse base 17.  Heptodecaphilia.
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