Discover Seattle!

General Category => Discover Seattle! => Topic started by: 49er on Mar 22 06 06:31

Title: how come
Post by: 49er on Mar 22 06 06:31
Phone number Calculator
Here is a math trick, can you figure the reason for the answer

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

Do you recognize the answer?

Title: Re: how come
Post by: P.C. on Mar 22 06 06:36
That is SO excellent. I've tried to figure that one out before, with no luck.  It's a pretty cool trick.
Title: Re: how come
Post by: Marik on Mar 22 06 07:32
WHAT?!?!? Nice trick!
Title: Re: how come
Post by: soapbox on Mar 22 06 07:45
WTF?

  could be a standard formula you have presented.this standard formula is applicable to all telephone directory systems????
Title: Re: how come
Post by: 49er on Mar 23 06 04:05
could be a standard formula you have presented.this standard formula is applicable to all telephone directory systems????[/DIV]
 just playing with numbers really........

  multiplying by 80, then 250.......is multiplying 20,000...the 4 zeros provide room for the last 4 digits of the phone number....this large number is divided by two which in effect the original 3 digits were multiplied by 10,000

  adding 1....multiplying by 250 = 250....which is deducted off in step 8

  the last 4 digits are added twice and divided by 2 = last 4 digits

  am I making sense?
Title: Re: how come
Post by: soapbox on Mar 23 06 04:34
yup.
Title: Re: how come
Post by: P.C. on Mar 23 06 05:05
 49er....am I making sense?



You could be.  I'm certain I wouldn't recognize it if you were.  I'm just going to stick with "Geee, what a neat trick".