Is this your phone number?

[emeleel]

Another one of those freaky "Do all this math stuff and you get a certain number" number puzzlers:

Key in the first three digits of your phone number into a calculator.
(DO NOT use your area code number)
Multiply by 80
Add one
Multiply by 250
Plus last four digits of your phone number
Plus last four digits of your phone number again
Minus 250
Divide by 2

[thinkerlady[$]]

My son's math teacher did this for him. He showed it to me, and of course I shared it with my classes. They were most impressed.

[poseidon]

No friggin' way. I've got three phone numbers here, and it works.

[amykhar]

Here's WHY it works.
Let X = your phone number (7 digits)
Let Y = the first 3 digits of your phone number
Let Z = the last 4 digits of your phone number

If you do the math, X is really only 10000Y + Z. (See it?)

So, the whole equation melanie gave us is:

((80Y + 1)250 + 2Z -250)/2 = 10000Y + Z

Stepping through it, you get"
(80Y + 1) 250 + 2Z - 250 = 20000Y + 2Z

Then,
(80Y+1)250 -250 = 20000Y

Next,
20000Y + 250 -250 = 20000Y

Finally, you get
20000Y = 20000Y or Y=Y. Therefore, it is true for any and all Y.

If you solve for Z, you also see that it is true for any and all Z because Z is cancelled out of the equation and is irrelevant.

Amy

[pluckyduck]

Ha!

I had that figured out before you did, Amy! Ha!

Andrea
bluffing.....still wondering how the refrigerator light knows when to go on

[Joubert[$]]

The refrigerator light is Z and is irrelevant.

[pluckyduck]

Okay, fine. Now explain this:

A thermos keeps things hot.
A thermos keeps things cold.

How does it know?

Andrea

[Joubert[$]]

Thermoes are Y. They add 250 degrees and then subtract 250 degrees.

Step through it like this:

Cold soda @ 40 degrees
Add 250 degrees
Soda is really hot
Subtract 250 degrees
Soda is now 40 degrees again -- delicious for sipping.

Z is still irrelevant.

[amykhar]

There's a little tiny guy who lives in the inner layer of the thermos. He dips his finger in the liquid and adjusts the temperature accordingly.

[pluckyduck]

Oh. Okay.

About those teensy guys inside my TV set.......how come there is 357 channels of them and nothing on?

Andrea

[amykhar]

Not sure I can do this one on line. But, let's try. Look at the monthly calendar here: http://www.eaforums.com/forums/calendar.php

You should be looking at Jan 2004, but any month will work as long as you tell me which one.

Once you are looking at the calendar, I need you to select any SQUARE area of the calendar (number of rows across = number of columns) To tell me the area you have selected, tell me the starting date (upper left corner) and the width of the square. For example, Jan. 4, with a width of 3 would give me all of the following dates: 4, 5, 6, 11,12,13, 18,19,20.

So, somebody pick a month and their square and post it here. And then we shall proceed.

[thinkerlady[$]]

ok--January 8--3 square

[emeleel]

Okay - January, 2 numbers square, starting with 23.

Next?

[amykhar]

OK. I am going to PM a number to Angie and one to Em. The number I send to em will be Angie's answer and the number I send to Angie will be Em's answer. BRB

Amy

[amykhar]

Now, Angie and Em, I need you to pick one number from each row in your square and one number from each column in your square and add them. Post the results here. Note: You can't pick more than one number from any row or column in your square.

Then, once Angie has posted, Em check your PM and post my answer. Same for Angie once Em has posted.

[thinkerlady[$]]

96
Row=48
Column=48

[emeleel]

Okay, my two numbers added together make 54.

And the number for Angie that Amy PM'ed me was 48!

[thinkerlady[$]]

Amy--how did you do that??

[amykhar]

thinkerlady said

96
Row=48
Column=48

Angie, not quite. It's hard to splain this in prose. You've essentially done what I told you to do twice and added the results.

[thinkerlady[$]]

Amy pm'd me 54 for you.

I added my rows and columns together--and got 96--but the rows = 48, and the columns =48.

Amy------------how did you do that?

[amykhar]

It's a quirk in calendars that any square area of the calendar, you can add ANY set of numbers where one number is in each row and one is in each column and the sum will be the same. So, all I had to do was add the diagonal of the each square and that told me the sum of the numbers you would pick.

Amy

[thinkerlady[$]]

Sorry. I am math challenged.

[amykhar]

And I am writing instructions online challenged