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BS: Isn't maths clever?

04 Oct 06 - 03:47 PM (#1850432)
Subject: BS: Isn't maths clever?
From: GUEST

1 x 8 + 1 = 9
12 x 8 + 2 = 98
123 x 8 + 3 = 987
1234 x 8 + 4 = 9876
12345 x 8 + 5 = 98765
123456 x 8 + 6 = 987654
1234567 x 8 + 7 = 9876543
12345678 x 8 + 8 = 98765432
123456789 x 8 + 9 = 987654321

1 x 9 + 2 = 11
12 x 9 + 3 = 111
123 x 9 + 4 = 1111
1234 x 9 + 5 = 11111
12345 x 9 + 6 = 111111
123456 x 9 + 7 = 1111111
1234567 x 9 + 8 = 11111111
12345678 x 9 + 9 = 111111111
123456789 x 9 +10= 1111111111

9 x 9 + 7 = 88
98 x 9 + 6 = 888
987 x 9 + 5 = 8888
9876 x 9 + 4 = 88888
98765 x 9 + 3 = 888888
987654 x 9 + 2 = 8888888
9876543 x 9 + 1 = 88888888
98765432 x 9 + 0 = 888888888


04 Oct 06 - 04:28 PM (#1850470)
Subject: RE: BS: Isn't maths clever?
From: Tannywheeler

Well, damn!!!! Ain't that a kick in the head? I'm glad you're staying out of trouble. How long did that take? Can you do another set? What got you started? Why?               Tw


04 Oct 06 - 04:33 PM (#1850478)
Subject: RE: BS: Isn't maths clever?
From: Kaleea

huh? yer hands git stuck at th' top o' th' keyboard er sumpin'?


04 Oct 06 - 04:46 PM (#1850496)
Subject: RE: BS: Isn't maths clever?
From: JohnInKansas

GUEST just got 'hold of an cipherin' text from ca. 1870, when the actually taught kids to do things with numbers like addin' an' subtractin'.

Those relationships, and other similar ones, were taught as aids to mental calculations - before all the "mental content" was abandoned in the grade schools.

John


04 Oct 06 - 04:57 PM (#1850506)
Subject: RE: BS: Isn't maths clever?
From: DMcG

There are analoguous results in base 8, 16, and so forth: indeed in every base. You get to maths, rather than arithmetic, when you can explain why!


04 Oct 06 - 05:07 PM (#1850509)
Subject: RE: BS: Isn't maths clever?
From: GUEST,lox

it is actally quite beautiful I think


04 Oct 06 - 06:34 PM (#1850580)
Subject: RE: BS: Isn't maths clever?
From: GUEST

number functions are beautiful. Kids can do neat things like multiply 243 X 11 in their heads. Answer is 2673. Taks about three seconds and no need to write it down. Number can indeed be beautiful.


04 Oct 06 - 06:44 PM (#1850588)
Subject: RE: BS: Isn't maths clever?
From: Q (Frank Staplin)

These numbers reminded me of my grandfather, who taught me the merchant's count many years ago when I was a small child. 4, 8, dozen, 16, 20, 24 ..... gross (twelve dozen or 144).

My grandfather was a merchant back around 1900, when dozens, grosses, etc. were the norm. I still count by fours, which drives my grandchildren nuts.


04 Oct 06 - 07:05 PM (#1850599)
Subject: RE: BS: Isn't maths clever?
From: catspaw49

Or run the times table on 9 and the answers from 1x9 to 10x9 are:

09...18...27...36...45...54...63...72...81...90

Note the numbers from 54 are inverts of the first series AND that the two digit answers all add to nine. I used that plus two of the above when I taught Math in a Vo-Tech where all the kids pretty much hated math and had done poorly before. All of a sudden they got curious and curiosity is one of the best things you can get to work with them.

Spaw


04 Oct 06 - 08:39 PM (#1850637)
Subject: RE: BS: Isn't maths clever?
From: Mr Happy

........u 4got to mention the other curious properties of 9!

Joh9n from h9ll! - [Where is he now??]

+

11 x 9 = 99, 9+ 9= 18, 1+8= 9.

12 x 9 = 108, 1+0+8 = 9.

Also fractions of 9 = 9


04 Oct 06 - 09:10 PM (#1850651)
Subject: RE: BS: Isn't maths clever?
From: GUEST,Jon

Just tried another base (hex) using 1 short of the 10.

1 x F = F
2 X F = 1E
3 x F = 2D
4 x F = 3C
5 x F = 4B
6 x F = 5A
7 x F = 69
8 x F = 78
9 x F = 87
A x F = 96
B x F = A5
C x F = B4
D x F = C3
E x F = D2
F X F = E1


04 Oct 06 - 09:19 PM (#1850657)
Subject: RE: BS: Isn't maths clever?
From: GUEST,Jon

Using octal gives:

1 x 7 = 7
2 x 7 = 16
3 x 7 = 25
4 x 7 = 34
5 x 7 = 43
6 x 7 = 52
7 x 7 = 61


04 Oct 06 - 09:30 PM (#1850661)
Subject: RE: BS: Isn't maths clever?
From: Mr Happy

no- I think yr a bit rong there!

Accordin' my calc's:

1 x 7 = 7
2 x 7 = 14
3 x 7 = 21
4 x 7 = 28
5 x 7 = 35
6 x 7 =42
7 x 7 = 49


04 Oct 06 - 09:41 PM (#1850666)
Subject: RE: BS: Isn't maths clever?
From: GUEST,Jon

Different number bases, Mr Happy. I was using my calc (which can do those bases) and thinking of what Dave had said above. It seems the "9 pattern" exits where you use 1 number less than what would be 10 in the base - ask a mathemetician to explain - I'm not one.

In decimal (base 10) we count

1,2,3,4,5,6,7,8,9,10,11...

In octal (base 8) we use the first 8 symbols and count

1,2,3,4,5,6,7,10,11..

In hex (base 16) we add a few letters of the alphabet to make the extra symbols and count

1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,10,11...


04 Oct 06 - 09:48 PM (#1850670)
Subject: RE: BS: Isn't maths clever?
From: catspaw49

There was a trick/joke thing the kids loved and old age seems to have erased it from my memory....and I thought I'd never forget it. Any help? It goes something like no matter how you manipulate the numbers, the answer is always the same.....and it's wrong. But you prove it's right by doinga new addition or subtraction or multiplication and every time you prove that the incorrect is answer is correct because you have done the function in some strange but seemingly logical way...................or something.....Ring any bells?

Spaw


04 Oct 06 - 10:00 PM (#1850675)
Subject: RE: BS: Isn't maths clever?
From: JohnInKansas

Spaw -

One of the "classic" trivial puzzlers is the one about the three hotel guests who each paid $10 for the room: Total $30.

The manager decides that 3 guys in a room is a bit much, so he gives the bellhop $5 to return to the 3 guys.

The bellhop can't figure out how to split the $5 three ways, so he gives each of the guests $1 and pockets the remaining $2.

Now each guest paid $10, but got $1 back, making the total paid by the guests 3 x $9 = $27. The bellhop kept $2, which makes $29.

What happened to the other $1?????

(There are numerous variations.)

John


04 Oct 06 - 10:46 PM (#1850695)
Subject: RE: BS: Isn't maths clever?
From: George Papavgeris

Er... correct, John, up to the last sentence:

...total paid by the guests 3x9=$27, (of which) the bellhop kept $2, which makes $25 to the hotel.


04 Oct 06 - 11:16 PM (#1850711)
Subject: RE: BS: Isn't maths clever?
From: NH Dave

According to Robert A. Heinlein, a well known Science Fiction author, kids learned heavy duty math in high school back in the early 1900's, and could do lots of math, including comparing different compound interest rates, that today's kids, if they can figure at all, do on a Scientific or Business calculator. Or perhaps only kids around Kansas and Missouri, Heinlein's home area, were taught such useful material.

Dave


05 Oct 06 - 02:46 AM (#1850748)
Subject: RE: BS: Isn't maths clever?
From: JohnInKansas

Dave -

ca. 1953, my junior hi math class (8th grade - in Kansas) was getting a little boring so to "get modern" I had to make myself a slide rule. It wasn't something taught as part of the standard course, but I had all I needed, from the regular classes, to figure out how to do it.

In 1968 I managed to "borrow" some time on the company "calculator" by staying over on a dead shift. The calculator was the latest thing, about the size of a small desk, that would add, subtract, multiply, and divide, and had one "storage space" where you could keep a single constant. I think they said they paid around $20,000 for it. Using 15-place log and trig function tables (entered by hand) it was a vast improvement over doing it all by hand.

Around 1974 I bought a "pocket calculator" for $125 from Sears Roebuck that would do quite a bit more than the 1968 era company machine. That's about the time that kids started taking calculators to High School classes, and were mostly allowed to use them - instead of learning how to do it themselves. Even then though, the kid had to know a little bit about which buttons to punch, and why.

Now the kids beg off with "well I don't have the right kind of calculator" and often get credit on the exams with that excuse.

John


05 Oct 06 - 03:32 AM (#1850768)
Subject: RE: BS: Isn't maths clever?
From: Paul Burke

Cue for Tom Lehrer's 'New Math', and shunt this thread above the line?


05 Oct 06 - 07:53 AM (#1850863)
Subject: RE: BS: Isn't maths clever?
From: Fibula Mattock

I was talking to someone yesterday who said she was teaching maths to a bunch of 15 year olds and none of them knew the 24hr clock or how to read a bus timetable. When she explained about the bus timetable they explained right back, and quite correctly, that in this country buses rarely, if ever, run to a timetable.

My favourite piece of maths is Suler's identity because it contains all the symbols you might want in a beautifully elegant way
(let's see if my html works):
e + 1 = 0


05 Oct 06 - 07:53 AM (#1850866)
Subject: RE: BS: Isn't maths clever?
From: Fibula Mattock

Suler? Euler! Damn my fingers!


05 Oct 06 - 07:57 AM (#1850870)
Subject: RE: BS: Isn't maths clever?
From: Fibula Mattock

(My other half disagrees about Euler, by the way. He claims vectors and tensors are much more interesting. We don't actually have a life, as you can tell.)


05 Oct 06 - 08:33 AM (#1850904)
Subject: RE: BS: Isn't maths clever?
From: Splott Man

catspaw49

One maths joke I know (I got it from Dr Sunshine) proves that 7 x 13 = 28.

It doesn't work written down, and you need an accomplice who plays dumb.


05 Oct 06 - 09:07 AM (#1850923)
Subject: RE: BS: Isn't maths clever?
From: Bunnahabhain

I could have sworn it was:

e ^ (Pi * i) - 1 = 0

but my serious maths is rarher rusty. Either way, it is very elegant.

copy-paste doesn't work with the HTML....


05 Oct 06 - 09:13 AM (#1850931)
Subject: RE: BS: Isn't maths clever?
From: TIA

T-shirt from my grad school days said

"Nerds are -e^(i*pi)"


05 Oct 06 - 09:42 AM (#1850960)
Subject: RE: BS: Isn't maths clever?
From: catspaw49

SPLOTT!!! That's it! As soon as I saw your post I remembered the whole thing. Thanks!

I'd do it on the board and these rough-edged teens would alternately try to explain how I was wrong and laugh their asses off as I "proved" I wasn't. Granted it was dumb. But you needed stuff like that and I had great success with kids who hated math.

Teachers must provide content but in today's world if you're not as entertaining as MTV, don't expect results.

Spaw


05 Oct 06 - 10:00 AM (#1850978)
Subject: RE: BS: Isn't maths clever?
From: Tannywheeler

Gosh, folks--I really enjoy hearing people talk "outland-furrin" languages a mile a minute. My eyes are crossing. But, because I know how numerically inept I am, I am super careful & do it 2 times(3 or 4, if the answers differ), and so I'm often accurate when Hubby, who passed Freshman Math in college & is cocky about his capability, has rushed the job & goofed. I guess I'm in Arithmetic, not MATH. But it's fun to watch others having fun.      Tw


05 Oct 06 - 10:22 AM (#1850999)
Subject: RE: BS: Isn't maths clever?
From: Helen

Fibula, the bus timetable reminds me of one of my favourite teacher jokes:

A teacher in a rural school is trying to use an example to teach subtraction. She says, "If I have nine sheep in a paddock and one jumps the fence, how many sheep do I have left?"

Little Johnny says, "None".

"No, that's incorrect. There were nine sheep, one jumps the fence, how many do I have left?"

Johnny says, "Miss, you have no sheep left".

"No, Johnny" says the teacher, "you don't seem to understand. I have nine sheep, one jumps the fence, how many have I got left?"

"No, Miss", says Little Johnny, "YOU don't understand. If one sheep jumps out, they all follow."


05 Oct 06 - 10:35 AM (#1851015)
Subject: RE: BS: Isn't maths clever?
From: jonm

There are only 10 sorts of people in the world; those who can count in binary and those who cannot.


Nobody has mentioned doing the nine times table (up to ten) on your fingers. You select the finger counting from the left for the multiple you want:

one, there are no fingers to the left, nine to the right so 1x9=09

two, there is one to the left, eight to the right, so 2x9=18

etc.

five, there are four to the left, five to the right so 5x9=45


05 Oct 06 - 11:20 AM (#1851057)
Subject: RE: BS: Isn't maths clever?
From: Peace

Country boy is away at college for years. He returns to his uncle's place years later. His uncle, proud of his nephew's accomplishments, asks him to say something profound in front of the assembled party guests. The nephew tries to beg off, but eventually, with blushing face he says, "Pi R Square." Many of the crown laugh, and one old boy says laughingly, "Hell, they didn't teach you nothin' at that college. Son, pie are round--CAKE are square!"


05 Oct 06 - 12:04 PM (#1851111)
Subject: RE: BS: Isn't maths clever?
From: Fibula Mattock

excellent - maths is funny as well as clever, and I have a love of geeks, so maths is sexy too.

I love the 9 times tables trick with the fingers - that's a new one to me.

I like the "rules" about whether numbers are divisible by other numbers, eg:
if a number is divisible by 2, it will end in an even number (yeah, that's the obvious one);
if a number is divisble by 3, add up the digits that make the number, and if they are divisible by 3, so is the number (works for 6 if divisible by 6, and 9 if divisible by 9 and so on);
etc etc, I'm sure there's a list somewhere!


05 Oct 06 - 12:08 PM (#1851114)
Subject: RE: BS: Isn't maths clever?
From: Fibula Mattock

I just picked up my 1st form (age 11-12) maths text book which I still have for some reason. One of the exercises listed begins:
"A mortar-shell is fired from a hillock 150m high and its subsequent height is observed at intervals of one second from the time of firing..."
- only in Northern Ireland would I get an education like that! Mind you, I should be grateful - Norn Iron schooling may be the best in the UK, but we were lucky to get text books up-to-date enough to have metres instead of feet in them. I distinctly remember my primary school maths text dealing in pounds, shilling and pence, and that was in about 1985.


05 Oct 06 - 12:14 PM (#1851123)
Subject: RE: BS: Isn't maths clever?
From: John MacKenzie

That's so's you can understand old fogeys like me Fibs, I don't count in old money, but metric is a jungle wherein I perish without trace.
Silly really, as some things sound so much bigger in centimetres ☺
Giok


05 Oct 06 - 06:33 PM (#1851476)
Subject: RE: BS: Isn't maths clever?
From: Nigel Parsons

Sorry Fibula:

Works for 3 or 9 every time (any multiple has the total of its digits as a multiple) But only works for six if the digits total a multiple of 6 and the last digit is even

CHEERS
Nigel


05 Oct 06 - 08:45 PM (#1851569)
Subject: RE: BS: Isn't maths clever?
From: jaze

Math has always been the absolute bane of my existence. I'm back in school working on a BS degree. I need to take a college level math course. I was thinking of trying it next semester. Already I have a terrible knot in my stomach. This one course could decide if I will eventually get my degree. I have vivid memories of math class in Catholic school. If we had 10 problems for homework and I did 9 of them , without fail, the one I couldn't do would be the one the nun sent me to the board to do. All the other kids would finish theirs and return to their seats. I would be left standing there without a clue. The nun would then pace back and forth behind me, rosary beads clinking and the hair on my neck standing up in anticipation of what was to come. Then she would make me face the class. She would pinch my cheek, then twist and BOOM BOOM BOOM she'd bang my head against the blackboard. I swear I saw stars and heard birds tweeting like in the cartoons.(of cousrse my friends were all sitting there about pissing their pants to keep from laughing) But this never helped my math ability. I hate math worse than leprosy! I'm now wondering two things:
1. Is there really anything on earth I want enough to take this class?
2. Is there a hynotist I can go to who can make me understand it?


05 Oct 06 - 09:26 PM (#1851606)
Subject: RE: BS: Isn't maths clever?
From: The Fooles Troupe

3. Can you find a lawyer to help you sue the school?


05 Oct 06 - 09:30 PM (#1851610)
Subject: RE: BS: Isn't maths clever?
From: The Fooles Troupe

Sorry...

Among the many things you are now wondering...

1. Is there really anything on earth I want enough to take this class?
2. Is there a hypnotist I can go to who can make me understand it?
3. Can I find a lawyer to help you sue the school?


05 Oct 06 - 10:11 PM (#1851665)
Subject: RE: BS: Isn't maths clever?
From: GUEST,jaze


05 Oct 06 - 10:13 PM (#1851667)
Subject: RE: BS: Isn't maths clever?
From: GUEST,jaze

yeah! like maybe she did damage to that part of my brain that helps me understand math. Yeah, maybe that'll work.


05 Oct 06 - 10:49 PM (#1851686)
Subject: RE: BS: Isn't maths clever?
From: Bassic

To9ite i was o9t on the t9wn with joh9n. D9nt tryt9 wor9 ou9 what the 9 i9....let9 just say9 it i9nt a constant9!999 john9 can do9 sums. 1 chikin9 tika and rise £1.90 pluz delifery. thats £20 tou9 you9 ma9e. and if yo9 are mouney....then i9s £30!