 Register to start posting
 Log in (after registering)
 Profile
 Personal Messages
 Search
| Author |
Message |
BarryA
Joined: 22 Dec 2006
Posts: 273
Location: Alford
|
Can anyone beat this?
Posted: Thu Jan 31, 2008 11:22pm
|
 |
|
I came across this link on a woodworking forum - watch it and answer the question in the topic
http://poi.5root.com/math-magic/
I know that I can't beat it.
_________________
You can only live once, but if you do it right, once is enough |
|
| Back to top |
|
 |
MysticMC
Joined: 04 Aug 2006
Posts: 4828
Location: Belgium
|
Posted: Thu Jan 31, 2008 11:37pm
|
|
|
Now that's amazing...  I wish I could do the same but I definitely can't  .
_________________
'I tell you : one must still have chaos in oneself to be able to give birth to a dancing star.'
(Friedrich Nietzsche, Thus spoke Zarathustra) |
|
| Back to top |
|
|
anax
Site Admin
Joined: 27 Jun 2006
Posts: 7434
Location: GrampianLife
|
Posted: Fri Feb 01, 2008 12:01am
|
|
|
Looks like magic, and it is in a way... but isn't there always a trick:
| Quote: |
Squaring Large Numbers
The algebraic identity A2 = (A+d) (A-d) + d2 can be used to square two-digit numbers in your head, almost as quickly as someone can do on a calculator. With practice, you can even square three-digit numbers (and higher) by this method. Let’s illustrate.
Given a two-digit number A, let d be the distance between A and the nearest “easy” number. (I define a number to be “easy” if it only has one nonzero digit.)
For example, to square the number 23, let d =3 and compute
232 = (26)(20) + 32 = 520 + 9 = 529.
...
Calendar Calculating
Finally, we end with an explanation of a skill that is as practical as it is entertaining: how to determine the day of the week of any date. We first describe the method before discussing its mathematical foundation.
Every day of the week is given a code number:
Sunday = 1
Monday = 2
...
Mathematical Magic
|
Not that I can do any of that... and am very entertained by watching such a clever entertainer
_________________
ENJOY GrampianLife.co.uk!  |
|
| Back to top |
|
|
MysticMC
Joined: 04 Aug 2006
Posts: 4828
Location: Belgium
|
Posted: Fri Feb 01, 2008 12:13am
|
|
|
I love watching him as well...
Thanks for the tricks...  . I'm going to do exercises
_________________
'I tell you : one must still have chaos in oneself to be able to give birth to a dancing star.'
(Friedrich Nietzsche, Thus spoke Zarathustra) |
|
| Back to top |
|
|
anax
Site Admin
Joined: 27 Jun 2006
Posts: 7434
Location: GrampianLife
|
Posted: Fri Feb 01, 2008 4:31am
|
|
|
| MysticMC wrote: |
| Thanks for the tricks... . I'm going to do exercises |
Well I'd enjoy testing you if you can master the trick.... it'd be a hit at parties
_________________
ENJOY GrampianLife.co.uk! |
|
| Back to top |
|
|
MysticMC
Joined: 04 Aug 2006
Posts: 4828
Location: Belgium
|
Posted: Fri Feb 01, 2008 5:42am
|
|
|
WoW I can already feel the pressure... I'll have to find a scene name if your tests are conclusive 
_________________
'I tell you : one must still have chaos in oneself to be able to give birth to a dancing star.'
(Friedrich Nietzsche, Thus spoke Zarathustra) |
|
| Back to top |
|
|
|
| |
  |
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum
|
|
|
|
|
|
