I mean, whoever came up with this just did it with trial and error, or what?  How would someone come up with the "procedure" to do this?

Enter the following in a calculator:

Enter the first three digits of your phone number (the exchange, not the area code)
Multiply by 80
Add 1
Multiply by 250
Add the last 4 digits of your phone number
Add the last 4 digits of your phone number, again
Subtract 250
Divide that number by 2
The result is ?

intersting...

The result is nothing I understand. What are you getting at?

Do you mean add the last 4 digits of your number as in 3456?

Or do you mean the last 4 digits as in 3+4+5+6 equaling 18?

Quoted: The result is nothing I understand. What are you getting at?

The result is your whole phone number.

Quoted: Quoted: The result is nothing I understand. What are you getting at? The result is your whole phone number.

I tried two different phone numbers and none of them worked. Maybe i am doing it wrong

Heh, that's kinda weird...

Quoted: Quoted: Quoted: The result is nothing I understand. What are you getting at? The result is your whole phone number. I tried two different phone numbers and none of them worked. Maybe i am doing it wrong

If your number is (789) 123-4567, you use the 123 part and the 4567 part, not the area code.

The result will be 1234567.

Hey, I've got another great trick!

First, give me your social security number...

ok, thats weird....

It's Algebra

    The way the problem is stated:

    C = {[A(80) + 1]250 + B + B - 250}/2

       = { 250(80)A + 250 + 2B - 250 }/2

        = 125(80)A + B = 10000A + B


        A = your exchange
        B = the last 4 of your phone number


      That's how it works.


Now take any number

- type it into your calculator, then
- type the same digits in again
  (for example, 247247)
- divide by 13
- divide by 11
- divide by 7
   What is the result?

Calculate this algebraically.

Let x = first three numbers
let y = last four numbers

(80x + 1)*250 +y + y -250
--------------------------------  =
                     2

250*80x + 250 + 2y -250
--------------------------------     =
                     2

10000*x + y

The first three digits of your phone number times 10,000 will add four zeros to the three digits, then add the last four digits to get to your original phone number.

This is no big deal. It ain't rocket science.

alright, its working for me now.

Quoted: Calculate this algebraically. Let x = first three numbers let y = last four numbers (80x + 1)*250 +y + y -250 --------------------------------  =                      2 250*80x + 250 + 2y -250 --------------------------------     =                      2 10000*x + y The first three digits of your phone number times 10,000 will add four zeros to the three digits, then add the last four digits to get to your original phone number. This is no big deal. It ain't rocket science.

Thanks.  That's what I was looking for.  Not only do I suck at math (I changed my major from engineering to a more friendly accounting back in college) but I don't think I could do long division anymore, much less anything else.

Here's a really crazy one too.

1) Type the first three digits of your phone number into a calculator.

2) Pause for dramatic effect.

3) Type in the remaining four digits.

4) ...

Quoted: Here's a really crazy one too. 1) Type the first three digits of your phone number into a calculator. 2) Pause for dramatic effect. 3) Type in the remaining four digits. 4) ...

Whoa!  It comes up with the phone number!!!

nm by the time I finished typing someone had already posted :P

How about the Jedi Mind Trick?


Just follow the instructions below:
   
DON'T scroll down too fast. Do it slowly and follow the instructions  below exactly, do the math in your head as fast as you can. It may help to say the answers aloud quietly.
   
   
FOLLOW these instructions one at a time and as QUICKLY as you can!
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
What is:
   
   
   
   
   
   
   
   
   
   
   
   
   
   
2+2?
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
4+4?
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
8+8?
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
16+16?
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
Quick! Pick a number between 12 and 5.
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
Got it?
   
   
   
   
   
   
   
Now scroll down...
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
The number you picked was 7, right?
   
   
   
   
   




Don't worry, only the weak-minded fall for it.