|
Author
|
Topic: Hope you lot ain't seen this one already...
|
|
|
Spiderman
Solid Nitrozanium Superfan!
Member # 1609
Member Rated:
|
posted July 07, 2006 12:24
Mmmmm, mathematical trickery. ![[Smile]](smile.gif)
Very similar to this: http://www.mysticalball.com/
I was called into the sales office the other day to explain how the link I just pasted works. These things are admittedly very clever...
--------------------
Math problems? Call 1-800-[(10x)(13i)^2]-[sin(xy)/2.362x]
Posts: 844 | From: Chicago | Registered: Aug 2002
| IP: Logged
|
|
|
|
Ashitaka
SuperFan!
Member # 4924
Member Rated:
|
posted July 07, 2006 13:18
There are only 9 possible answers to this problem. They all have the same symbol, and are divisible by 9.
--------------------
"If they're not gonna make a distinction between Muslims and violent extremists, then why should I take the time to distinguish between decent, fearful white people and racists?"
-Assif Mandvi
Posts: 3006 | From: Switzerland | Registered: Feb 2006
| IP: Logged
|
|
Spiderman
Solid Nitrozanium Superfan!
Member # 1609
Member Rated:
|
posted July 07, 2006 13:59
There's a bit more to it than that.
This relies on the magic number 9 again (7 Up puzzle comes to mind).
Take any number. 32 for example. This can also be expressed as 10*3 + 2.
With the game, it asks you to subtract the sum of the digits of the number from the number, which can be expressed as follows:
10*3 + 2 - (3 + 2) = 9*3 = 27
More generically: 10*a + b - (a + b) = 9a
As this number is always predictable, the symbols used are all the same, scattered throughout the myriad of other symbols which exist merely as a distraction.
They change the symbol each time you play, but they change *every* appropriate symbol. They only give you 10 seconds, but notice all the other symbols of the same type, and you'll notice they're all multiples of 9.
Again, very clever. The first time encountering this kind of puzzle can be flabbergasting.
--------------------
Math problems? Call 1-800-[(10x)(13i)^2]-[sin(xy)/2.362x]
Posts: 844 | From: Chicago | Registered: Aug 2002
| IP: Logged
|
|
maybe.logic
Alpha Geek
Member # 5014
Member Rated:
|
posted July 10, 2006 07:35
quote:
Originally posted by Spiderman:
There's a bit more to it than that.
This relies on the magic number 9 again (7 Up puzzle comes to mind).
Take any number. 32 for example. This can also be expressed as 10*3 + 2.
With the game, it asks you to subtract the sum of the digits of the number from the number, which can be expressed as follows:
10*3 + 2 - (3 + 2) = 9*3 = 27
More generically: 10*a + b - (a + b) = 9a
As this number is always predictable, the symbols used are all the same, scattered throughout the myriad of other symbols which exist merely as a distraction.
They change the symbol each time you play, but they change *every* appropriate symbol. They only give you 10 seconds, but notice all the other symbols of the same type, and you'll notice they're all multiples of 9.
Again, very clever. The first time encountering this kind of puzzle can be flabbergasting.
It was'nt flabbergasting for me ![[tired]](graemlins/tired.gif) as it has never worked ![[ohwell]](graemlins/ohwell.gif)
Posts: 345 | Registered: Mar 2006
| IP: Logged
|
|
Ashitaka
SuperFan!
Member # 4924
Member Rated:
|
posted July 10, 2006 07:46
It is really easy to blow peoples minds by doing square roots in your head, and believe it or not it is not very difficult. Most people today wouldn't even know how, without a calculator, to get a square root. Though it's been done in peoples head since the days of ancient egypt.
Here's my link on how to do it, though there are probably better explanations if you just google it.
How to do square roots in your head
--------------------
"If they're not gonna make a distinction between Muslims and violent extremists, then why should I take the time to distinguish between decent, fearful white people and racists?"
-Assif Mandvi
Posts: 3006 | From: Switzerland | Registered: Feb 2006
| IP: Logged
|
|
canadiangeek
Geek
Member # 4946
Member Rated:
|
posted July 10, 2006 08:16
Ashitaka,
I didn't realize it was that easy... I feel like a shame to the geek community
Posts: 161 | From: Nova Scotia | Registered: Mar 2006
| IP: Logged
|
|
maybe.logic
Alpha Geek
Member # 5014
Member Rated:
|
posted July 10, 2006 11:19
I second that, I just used to use factorisation, ooohh that was very boring!
Posts: 345 | Registered: Mar 2006
| IP: Logged
|
|
|
|
The Famous Druid
Gold Hearted SuperFan!
Member # 1769
Member Rated:
|
posted July 10, 2006 15:19
Don't they teach the young geeks anything these days?
I was taught that square root 'trick' when I was 14, it's a natural outcome of a bit of very basic algebra.
(a+b)^2 = a^2 + 2ab + b^2
Using the numbers from the example, if you're trying to find sqrt(79), and your guess is 9, and you know there's a (smallish) error 'e' in your guess, then
79 = (9 + e)^2 = 81 + 18e + e^2
If e is small, then e^2 will be very small, so don't worry about it.
This leaves you with
79 = 81 + 18e
-2 = 18e
e = -2/18
so your approximate square root is 9 - 2/18
--------------------
If you watch 'The History Of NASA' backwards, it's about a space agency that has no manned spaceflight capability, then does low-orbit flights, then lands on the Moon.
Posts: 10313 | From: Melbourne, Australia | Registered: Oct 2002
| IP: Logged
|
|
Ashitaka
SuperFan!
Member # 4924
Member Rated:
|
posted July 11, 2006 00:07
quote:
Originally posted by The Famous Druid:
Don't they teach the young geeks anythng these days?
No they don't. Well not in Indiana at least. My mother is a math teacher in a high school . She is not allowed to disallow 4 function calculators to her low students. Students don't even remember the multilication table any more becuase they never have to use it.
--------------------
"If they're not gonna make a distinction between Muslims and violent extremists, then why should I take the time to distinguish between decent, fearful white people and racists?"
-Assif Mandvi
Posts: 3006 | From: Switzerland | Registered: Feb 2006
| IP: Logged
|
|
maybe.logic
Alpha Geek
Member # 5014
Member Rated:
|
posted July 11, 2006 03:33
That is a very good point Ashitaka, I have a few friends who have children doing A level maths, which is a decent level, and they can do all of the "theory" (via calculator) but ask them to try some mental arithmetic, they are about as advanced as a 10 year old, it is quite embarrassing to listen to the poor answers. ![[weep]](graemlins/weep.gif)
Posts: 345 | Registered: Mar 2006
| IP: Logged
|
|
|
UBBFriend: Email this page to someone!
Printer-friendly view of this topic
