Math Puzzle

Ateneo de Manila Professor Queena N. Lee-Chua, in her column Eureka! in the Philippine Daily Inquirer (page B4) gave this Math puzzle today (March 4, 2006):

1. Key in the first three digits of your seven-digit phone number into the calculator. (Note: Do not key in the area code, but the three digits after.)

2. Multiply by 80.

3. Add 1.

4. Multiply by 250.

5. Add the last 4 digits of your phone number.

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

7. Subtract 250.

8. Divide by 2.

Amazing, right? I love this puzzle. I emailed my solution/explanation to this puzzle.

This can also work for cellphone numbers if you use only the last seven digits (ie d not include 0916, 0917, 0918, 0920, 0906, or whatever the first four digits of your mobile number is) of your mobile number.


Manang K said...

interesting. so how does it work? :-)

ria said...

I'll post the solution next week. I don't want to pre-empt the column writer who will publish it next week.