What you know about math?

Submitted By: Gath from Sudoku.com.au

93 Comments
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ap  From Boston
aha!this is just fine..think i shall also add some science snippets here..been thinking why not you do such thing for ppl like me who love to share some stuff i read relating to those subjects..you read my mind Gath!will just flood this page ,but must have time to do so!
cheers
anu
04/May/07 9:49 PM
ap  From Boston
ok now some lil things i know abt Math
Math is the language God used to write the universe.
and the definition of God:He who can properly define and divide is to be considered a God.
also unless otherwise proclaimed Integer, God is REAL!!
04/May/07 10:48 PM
JL  From Alaska    Supporting Member
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Haha, I love it. Math rules!
07/May/07 3:22 PM
appy  From boston
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Old Euclid drew a circle
On a sand-beach long ago.
He bounded and enclosed it
With angles thus and so.
His set of solemn greybeards
Nodded and argued much
Of arc and of circumference,
Diameter and such.
A silent child stood by them
From morning until noon
Because they drew such charming
Round pictures of the moon.
Vachel Lindsay
07/May/07 9:40 PM
appy  From boston
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and my all time fav is this...
Points
Have no parts or joints
How then can they combine
To form a line?
07/May/07 9:44 PM
appy  From boston
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Interesting..have you ever observed a glaring fact? Six Nobel Prizes are awarded each year, one in each of the following categories: literature, physics, chemistry, peace, economics, and physiology & medicine. Notably absent from this list is an award for Mathematics. The reason for this conspicuous omission has been subject of extensive speculations. But, maybe the main reason for this is that Nobel, an inventor and industrialist, did not create a prize in mathematics simply because he was not particularly interested in mathematics or theoretical science. His will speaks of prizes for those ``inventions or discoveries'' of greatest practical benefit to mankind.
09/May/07 9:28 PM
   billy  From Perth    Supporting Member
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Can someone pls work out how this is done? appy? being the mathematician that you are luvvie...

1. First of all, pick the number of times a week that you would like to go out to eat.
(more than once but less than 10)
2. Multiply this number by 2 (just to be bold) 3. Add 5
4. More...


Multiply it by 50
5. If you have already had your birthday this year add 1757 ....
If you haven't, add 1756.
6. Now subtract the four digit year that you were born.


You should have a three digit number

The first digit of this was your original number
(i.e., how many times you would like to go out to restaurants in a week.)
The next two numbers are YOUR AGE! (Oh YES, it is!!!!!)
13/May/07 5:43 PM
JL  From Alaska    Supporting Member
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Let 'x' be your 1-digit number for your step 1. Let 'y' be your birth year. Following that algorithm without simplifying anything, you get this mathematical statement:

[(2x+5)*50] + 1756 (or 1757) - y

Distribute the 50. Also, I haven't had my birthday yet this year, so I'm using 1756:

100x + 250 + 1756 - y

250+1756 = 2006, so

100x + 2006 - y

(obviously, if you had your birthday already 250+1757 = 2007...familiar?)

My birth year is 1980, and as I said I've not had my birthday yet, so...

100x + 2006 - 1980 = 100x + 26. Abusing notation, the three digit number is x26. How about that, I am indeed 26! Amazing? Not really.

I've seen this one before, but the numbers were different. Next year, the magic numbers will be 1757 and 1758. Why? Just add 250, and you'll get the previous year and the current year numbers respectively. Your original number is multiplied by 100 in 2 steps. As long as you're not 100+, it's not going to be affected by any future calculation.

It's a cute trick, naught more.
13/May/07 8:01 PM
   billy  From Perth    Supporting Member
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OMG JL - do you know how long it is since i've had to work out the value of x?? ok - it's a long time...my brain is now having a seizure and I thank you muchly for setting it out in a way a blonde would really appreciate...
13/May/07 10:44 PM
ap  From india
Beatcalc
well are you the type who get a bit miffed on seeing ppl using the calc even for simple two digit multiplication?you can elate yourself by following this method to give out the squares of two digit numbers w/o the calc and humble those guys!!
to start with we shall see the squaring of numbers starting with '5'
simple 4 steps
1.take a 2 digit number starting with 5(lets take 52)
2.suare the first digit.(that is 5 square)
3.Add this to the second digit.this is the first part of the ans.(5 square plus 2.that is 27)
4.square the second digit.this is the second part of the ans(2 square=4,ie 04)
2704 is the square of 52.
more to come
cheers

3.Now square the second digit.
29/May/07 3:02 AM
ap  From india
the last step is repeated plz ignore
29/May/07 3:04 AM
appy  From india
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today we will see how the numbers in 20s be squared..
Square the last digit (keep the carry) _ _ X
Multiply the last digit by 4, add the carry _ X_
The first digit will be 4 plus the carry: X _ _
Example:say the no is 24
Square the last digit (keep the carry):
4 × 4 = 16 (keep 1) _ _ 6
Multiply the last digit by 4, add the carry:
4 × 4 = 16, 16 + 1 = 17 _ 7 _
The first digit will be 4 plus the carry:
4 (+ carry): 4 + 1 = 5 5 _ _
So 24 × 24 = 576.

30/May/07 2:25 AM
   jamie  From aggieland texas    Supporting Member
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appy - I will try to get back here more regularly. I will be thinking about 'stuff' to share.
Your 'tricks' are part of a contest we have in Texas called Number Sense. The students have 80 questions to answer in 10 minutes. No scratch work, no erasing or crossing out, just write the answer. Also, any problem skipped is wrong. Every tenth problem is an estimation problem - bigger numbers in which the answer must be within 5% or the correct answer.
It is amazing to watch the really good kids at work. Much of it is knowing shortcuts, but there is also a lot of really good mathematics involved. The questions cover everything from simple algebra problems up through calculus.
01/Jun/07 3:12 AM
ap  From india
Music is nothing but applied mathematics..for if you look at the characterestics of a musical note from an instrument we can clearly see the combinations of sine waves..(er then can the musicians be called as apllied mathematicians!)
well can you guess what is the instrument that produce the graph closest to f(x)=sin(x)?or in other words a purest tone producer??
ANS:Flute
and the human voice produces the most complex sine wave....
02/Jun/07 1:48 AM
   nal  From miami    Supporting Member
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Oh how I needed this at the supermarket a couple of days ago. Long story made short: Cashier makes an error and charges the woman for 4 items when she only bought 3. This is how the woman's bill looked like
+ 1.00 + 1.00 + 1.00 + 1.00 - 1.00
=$3.00
The woman insisted she was charged for 5 items
04/Jun/07 10:48 PM
   Jimmy  From Scotland
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An old one but one I still like, reminded by nal's comment above:-

Three ladies in a restaurant have lunch. The bill comes to $27 so they each give the waiter a ten dollar bill = $30. At the till the manager points out to the waiter that the bill should have only been $25. The waiter, realising that the ladies won’t know, gives each lady back her $1 change and pockets the other $2.

$30 was handed over.

Each lady paid $9 = $27 plus the $2 in the waiters pocket = $29.

Who has the missing dollar???
05/Jun/07 10:38 PM
   Rola  From Perth    Supporting Member
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Jimmy from Scotland
answer from #2 son
the ladies have $3
the waiter has $2
and the till has $25

3+2+25 = 30
:D
07/Jun/07 1:39 PM
   Rola  From Perth    Supporting Member
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Jimmy from Scotland

answer from #1 son

the manager!
07/Jun/07 3:19 PM
appy  From india
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'Vedic Mathematics' is the name given to the ancient system of mathematics, or, to be precise, a unique technique of calculations based on simple rules and principles, with which any mathematical problem — be it arithmetic, algebra, geometry or trigonometry — can be solved, hold your breath, orally!
The system is based on 16 Vedic sutras or aphorisms.These 16 one-line formulae originally written in Sanskrit, which can be easily memorized, enables one to solve long mathematical problems quickly.
08/Jun/07 2:07 PM
   Jimmy  From Scotland
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Rola - #2 Son gets the coconut
08/Jun/07 9:44 PM
   Rola  From Perth    Supporting Member
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I'll let him know Jimmy...
09/Jun/07 12:45 AM
   Rola  From Perth    Supporting Member
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Appy:
both Son #1 and #2 answer to the maths question on easy:
Quad sided Pyramid ..
14/Jun/07 6:26 PM
appy  From india
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oh my!so quick??well can i give out the ans or shall we wait for some more guess?
14/Jun/07 6:39 PM
   Rola  From Perth    Supporting Member
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you can wait for some more answers Appy...
14/Jun/07 6:44 PM
appy  From india
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ok,but from the nature of it i reckon very few will be there..what do ya say Rola?
14/Jun/07 6:54 PM
   Rola  From Perth    Supporting Member
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you could wait till the Americans are up.. a bit too early yet for them to be up yet. the east coast is nearly 5.00am....
14/Jun/07 6:59 PM
appy  From india
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yeah may be!!still high hopes..
14/Jun/07 7:00 PM
   Rola  From Perth    Supporting Member
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Looking at who has been on this page.

Jamie, Jimmy, Kim/Florida, they are all maths experts.. they should be given the chance to answer...
14/Jun/07 7:01 PM
   Rola  From Perth    Supporting Member
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my boys (18 and 21) are good with maths, especially #1..
14/Jun/07 7:03 PM
appy  From india
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right..shall wait til they show up..its a simple ans and i will let you know the link i got it..for its a bit long to explain the math behind it..
now off i go for a dinner..the invitation is from quite un unexpected person,motherinlaws sister..
lemme make use of the oppurtunity to the max extent possible..
cheers
14/Jun/07 8:47 PM
   Jimmy  From Scotland
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Haven't figured this one out yet, but don't think it is a four sided pyramid. Visually in my head I would agree but logically not. First off, in the resulting pyramid, there would be three edges coming down from the apex, creating three faces, each half the size of the cubes original face. The bottom side would be newly cut. So each pyramid (2) has 3 x 1/2 original face means total = 3 original face areas. Not enough since the cube had 6?
14/Jun/07 10:30 PM
   Jimmy  From Scotland
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Simpler explanation than above. In your mind try sticking the two pyramids back together to make the cube? It doesn't work.
14/Jun/07 10:32 PM
   Jimmy  From Scotland
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OK Think I have it. Hard to picture, never mind describe. Start with the four sided pyramid as per Rola's sons answer. Sit it on a surface and then cut off the three points at an angle. This leaves a seven sided polygon where three sides are 2/3 of each original cube face, three sides are 1/3 of the cube face and the last is the cut face which is a hexagon?

Now draw it
14/Jun/07 10:48 PM
   Jimmy  From Scotland
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Oh and you have two of them.
14/Jun/07 10:49 PM
   Jimmy  From Scotland
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/\
/ \
/ \
/_\ _/_\

Test - Think Gaths software may remove all the spaces?
14/Jun/07 10:53 PM
   Jimmy  From Scotland
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Yup
14/Jun/07 10:53 PM
   Jimmy  From Scotland
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....../\
...../..\
..../....\
.../\..../\
../__\__/__\

Ignore the dots?
14/Jun/07 11:07 PM
   Jimmy  From Scotland
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Oh sod
14/Jun/07 11:08 PM
   Jimmy  From Scotland
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....../\
...../..\
..../....\
.../\..../\
../_\_/_\

O nce more?
14/Jun/07 11:09 PM
   Jimmy  From Scotland
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Back to work, Thanks appy.
14/Jun/07 11:10 PM
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