26 September 2006

Mind reader? I wasn't born yesterday.

I found this flash game on Adam's cartoonlife. While Adam thinks he might be too credulous or this game is quite clever, I can just see through the hoax. It's just a mathematical trick.

Say we have 10p+q as our two-digit number, when we add together both digits, we get p+q.

If we substract the total of these two digits from the original number, we have (10p+q)-(p+q), which is indeed 9p.

Hence, whatever two-digit number we have, the final number is always a mutiple of nine. By the way, since p is no greater than 9, 9p would merely be 9, 18, 27, 36, 45, 54, 63, 72 or 81.

Now have a closer look at the chart. Have you notice that in the chart the symbols next to 9, 18, 27, 36, 45, 54, 63, 72 and 81 are all the same, though it changes every time when you click 'Try again'. Obviously, symbols next to other numbers are just red herrings.

There is no magic; whenever you are amazed by certain magic, you are just beguiled by a neatly designed device.


cartoonlife said...

Thanks Wei, I knew there was a trick to it, I was just too buffetted around by the winds of fate to be able to work it out- thus the beauty of blogging- put it to the board and let someone smarter than me work it out!

kangaroo said...

very interesting! I like it.