Phone math test

[Stephen]

1. Grab a calculator. (you won't be able to do this one in your head).

2. Key in the first three digits of your phone number (NOT the area
code).
3. Multiply by 80.
4. Add 1.
5. Multiply by 250.
6. Add the last 4 digits of your phone number.
7. Add the last 4 digits of your phone number again.
8. Subtract 250.
9. Divide number by 2.

Recognise the answer you get?

Stephen

 

[DewKnight]

bling blingage

 

[wicked_gal00]

It's actually pretty simple, and not so impressive :p

Let x = the number formed by the first 3 digits of your phone number
and y = the number formed by the last 4

Then by following the steps you get:

((80x + 1)*250 + 2y -250)/2
=(20000x + 250 + 2y - 250)/2
=10000x + y

From here it's easy to see how this gives you your phone number again. Lets say your phone number is 123-4567, then if follows that:

10,000*(123) + 4567 = 1,230,000 + 4567 = 1,234,567 (or 123-4567)

There you go! :D

 

[Stephen]

True. I knew how it was done, I just thought it would be fun for some members.

Stephen

 

[wicked_gal00]

I know.. I just wanted to be nerdy :p

 

[Eric]

Kinda cool I guess. And, not to brag, but no calc for me, worked it out in me head :gl:
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Yeahhhhhhhhh Riiiiiiiiiiiiiiiiiight, :p :lol:

-Eric

 

[ThreeD]

damn, didn't work here in Norway :D Cool outcome with the phone number I had in the US though hehe..

 

[narutoman]

that is really cool
i get exactly same as my phone number

 

[Fewski]

I did it 3 times and it doesn't work for my number.

I have a "0" in the first digit place in my last 4 digits, so I wonder if that messed it up?

 

[Morph]

Didnt work for my UK number.

 

[Stephen]

I did it 3 times and it doesn't work for my number.

I have a "0" in the first digit place in my last 4 digits, so I wonder if that messed it up?

Worked for me, and my phone number is xxx.0580

Stephen

 

[GJ]

Didnt work for my UK number.

Thought so.....

 

[PolurNET]

Didnt work for my UK number.

Thought so.....

:lol: As I've been saying, Americans are weird... oops, so as Canadians with 7-digit phone numbers :red:

Cool math, why not post some Calculus, I'd be interested