Thursday, March 06, 2008

More fun with numbers -- the telephone game

A math teacher in real life, Andrée was complimentary about my most recent post about happy numbers.

Thus encouraged, although I knew I was pushing my luck, I was brave enough to try this brain teaser that I stumbled on at this site.

The directions on the original site call for using a calculator. Andrée, if you let your students try this, I hope you'll insist on pencil and paper instead -- it's the Curmudgeon in me.

Anyway, here's the deal:

1. Key in the first three digits of your phone number (not the area code -- what we mature individuals call the 'exchange')

2. Multiply by 80

3. Add 1

4. Multiply by 250

5. Add the last 4 digits of your phone number (yes, this is designed for seven digit phone numbers)

6. Add the last 4 digits of your phone number again

7. Subtract 250

8. Divide number by 2

The answer should look very familiar.

I tried it on three different phone numbers... and it worked each time.


Empress Bee (of the High Sea) said...

this made my head spin around, is it supposed to make my age?

smiles, bee

Jean-Luc Picard said...

I think I've seen this before. Fascinating .

Skittles said...


I found this and wanted to share it with you.