Interesting and easy math game

[Ghoulish Delight]

Originally Posted by scaeagles

I was able to figure out the secret to that one after just 2 tries. I still can't figure out the math behind the one I posted and why it works every time. Except for WB. I'm think the problem isn't with the game, though, WB.

Well, if X=the first 3 digits of your phone number and Y=the last 4, then your phone number can be represented as 10000X+Y

So, the operations you perform look like this:

(80X+1)*250+2Y-250
___________________
2

Simplifying the numerator, you get 20000X+250+2Y-250.

The +250 and -250 cancel out, leaving you with 20000X+2Y. Divide that by 2 and you get 10000X+Y, which of course is your phone number.

[wendybeth]

Originally Posted by Ghoulish Delight

Well, if X=the first 3 digits of your phone number and Y=the last 4, then your phone number can be represented as 10000X+Y

So, the operations you perform look like this:

(80X+1)*250+2Y-250
___________________
2

Simplifying the numerator, you get 20000X+250+2Y-250.

The +250 and -250 cancel out, leaving you with 20000X+2Y. Divide that by 2 and you get 10000X+Y, which of course is your phone number.

My brain hurts just looking at that.

[scaeagles]

Yep - makes total sense now. Good old algebra - who said we'd never need it for anything useful?????

[Ghoulish Delight]

Lizziebith's link works on a similar principal.

any 2 digit number can be represented by the equation 10X+Y where X and Y are between 1 and 9.

So, the euqation this time is (10X+Y)-(X+Y). That equals 10X+Y-X-Y, which equals simply 9X. Since X can only be 1-9, the only possible solutions are 9, 18, 27, 36, 45, 54, 63, 72, and 81. So, like scaeagles said, they just seed those 9 numbers with the same symbol and voila, esp.

[lizziebith]

I am so impressed! Mind you I loved algebra, but it was not easy. I sweated blood for that A. And I've found it's like a foreign language; I lose it if I don't use it. Now, I DO understand those equations, but it would have taken me about a week to actually come up with them (if ever)!

[Ghoulish Delight]

Here's another one, similar to Lizzie's but the trick isn't based on mathematics. It's a clever one.

http://www.snopes2.com/humor/info/card1.htm

[lizziebith]

So much fun! I'm loving this stuff...keep it coming, guys!!

[Dippy Dawg]

Originally Posted by Ghoulish Delight

Here's another one, similar to Lizzie's but the trick isn't based on mathematics. It's a clever one.

http://www.snopes2.com/humor/info/card1.htm

took me a couple turns before I remembered that one