1) Key-in the first 3 digits of your phone number into the calculator
(not the area code)
2) Multiply by 80
3) Add 1
4) Multiply by 250
5) Plus last four digit of phone number
6) Plus last four digit of phone number again
7) Minus 250
8) Divide by 2
Is it your phone number?

Not Amazing, just simple arithmetic!

Okay, let's take your first 3 digits...Let's say it's ABC. This number can be expressed as A-Hundreds plus B-tens plus C. Follow me so far.

Okay, so this equals:
100A + 10B + C

When we multiple by 80 (Hmmm...I wonder where 80 came from, we'll see soon) we have:
8000A + 800B + 80C

Okay, Now we must add 1, so we have:
8000A + 800B + 80C + 1

Now we multiply by 250, so this leaves:
2000000A + 200000B + 20000C + 250
(You can now begin to see why 80 was chosen...nice round numbers that are 2 times multiples ot 10. Also, note the 250 term at the end.)

Okay, next we must add our last four digits. Let's say my last four digits are DEFG. This number is in the thousands and can be expressed as:
1000D + 100E + 10F +G

So, when we add it to what we were left with before, we have:
(2000000A + 200000B + 20000C + 250) + (1000D + 100E + 10F +G)

We add it again and now have:
(2000000A + 200000B + 20000C + 250) + (1000D + 100E + 10F +G) + (1000D + 100E + 10F +G)

This can be reduced to:
(2000000A + 200000B + 20000C + 250) + 2(1000D + 100E + 10F +G)

When we multiply through by our by two:
(2000000A + 200000B + 20000C + 250) + (2000D + 200E + 20F +2G)
(How convenient, all the terms are now two times multiples of ten)

Anyway, now we subtract our 250(remember that) and the positive 250 term goes away:
(2000000A + 200000B + 20000C) + (2000D + 200E + 20F +2G)

All that's left is to divide by 2(imagine that), so we are left with:
(1000000A + 100000B + 10000C) + (1000D + 100E + 10F +G)

Voilla: Add the terms up and we have a number that looks like:

ABCDEFG

Couldn't you just say that it was, "Simply amazing"?

LOL! Yep, that would have worked too.

Baja Daze,

Where do you get this stuff!

Amazing.

Julie

HUH!

BAJA DAZE, you have way to much time on your hands!!

I've seen the trick before, never had it explained. Surprisingly simple. Thanks Baja Daze, that was interesting.

Geez Bajadaze...............my head is still spinning!!!!!!

Thanks guys! I live for this stuff...It's almost therapeutic.