More Fun With Numbers

[Southern Man]

I wonder who has the time to come up with this stuff?


Another one of those mathematical enigmas:

1.) Put the first 3 digits of your phone number into a calculator (not
your area code)

2.) Multiply by 80

3.) Add 1

4.) Multiply by 250

5.) Plus last 4 digits of your phone number

6.) Plus last 4 digits of your phone number again

7.) Minus 250

8.) Divide by 2

Result: Your phone number

[Staz]

Hey Rube Goldberg, watch this?

Step 1. insert your phone #

Result: your phone #

[Southern Man]

Originally Posted by Staz

Hey Rube Goldberg, watch this?

Step 1. insert your phone #

Result: your phone #

Hey, I don't come up with this stuff... I just pass it along. I was curious about it because you put the number in, in two parts and do a lot of calculations along the way. The result is the phone number in whole. I'm sure it looks very simple to a math wizard but you know how us South Carolina Rubes are. Just show us something shiny and we are amazed for hours....

[Staz]

I'm no math genius. Also I could never figure it out either.

It just seemed so Rube Goldberg ish to me.

Stuff like that is fun the first time. But watching someone try to figure out how to sharpen a pencil in 20 steps or more begs for someone to stick a pencil in a pencil sharpener and then turn the handle. Or even better, use a battery operated pencil sharpener.

My version of a battery operated pencil sharpener.

Step 1. Speed dial #1

Result: Calls home phone #

[Southern Man]

Originally Posted by Staz

Step 1. Speed dial #1

Result: Calls home phone #

Your so wrong Staz.......

I just pushed speed dial #1 and it wasn't your phone number.

[Staz]

Your right!

I ussually use my cell but I just tried speed dial 1 on my home phone and got my mother in law! Yuck!

[Southern Man]

Originally Posted by Staz

Your right!

I ussually use my cell but I just tried speed dial 1 on my home phone and got my mother in law! Yuck!

Mother-in-Laws are here for some reason.... I just haven't figured it out yet. I have enough anguish and guilt without her help.

Clarification.... I no longer have someone else's mother to give me grief so I'm a lucky man I guess. I divorced her when I divorced her daughter.

[stigweed]

this is me trying to avoid doing any more maths work. i woe up last night trying to prove things about the identity matrix in my head and going over a program i wrote to test if a number is even or not. too much maths at uni. or maybe too much red bull before bed... anyway:

here's why it works.

multiplying by 80, adding 1, multiplying by 250 and subtracting 250 is the same as doing 80 * 250 = 20000. ((80+1)*250 - 250 = 20000) multiplying this by the first 3 digits of you phone numbers (say a,b,c) gives you double that number, moved along a few decimal places which equals 2(a,b,c)0000. (see where this is headed yet?)

adding the last 4 digits (say d,e,f,g) twice gives you 2(a,b,c)2(d,e,f,g). Dividing by two gives you the numbers you started with a,b,c,d,e,f,g. This is because you can swap the stages of subtracting 250 and adding the 4 digits around. (+,- associative) This should only work for 7 digit numbers.

Theres some abuse of notation going on in there but I can't tthinnk how else to write it. Thankyou.

[stigweed]

it's about now, having looked upon the full horror of how much my mind is doing that i realise i really ought to just chill out and have a smoke instead...