11/27/2006

Neat Math Trick… Taken to a Geekier Level

My Grandpa forwarded me a neat math trick which you should try:

  1. Grab a calculator.
  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

The amazing result: Your entire phone number. This is a neat trick. But, being the ubergeek that I am, I had to figure out how it works.

First Step: Write out the instructions as a math equation. Let the first three digits of the phone number be ‘X’ and the last 4 digits be ‘Y’. The expected result will be 10000X + Y (your entire phone number).

[250(80X + 1) + 2Y - 250] / 2 = 10000X + Y

Next Step: Reduce the equation.

[20000X + 250 + 2Y - 250] / 2 = 10000X + Y

[20000X + 2Y] / 2 = 10000X + Y

10000X + Y = 10000X + Y

Final Step: It checks out, both sides are equivalent. Isn’t math fun!

5 Comments

  1. Well, it’s official. You’re even dorkier than I could have ever imagined 🙂

    Comment by Nick — 11/28/2006 @ 10:40 am

  2. Hey man what’s going on? Shoot me back an email some time.

    Comment by Craig — 1/31/2007 @ 3:08 pm

  3. Is that what you get to do with your free time? Man, I need to change jobs 😉 Hope you are doing well. From the pics, you look happy.

    Comment by Alan Antiporda — 1/31/2007 @ 3:16 pm

  4. The main page of a site has especially pleased. Good color scale! Thanks!

    Comment by Selah — 5/17/2007 @ 9:40 am

  5. Geld nodig. Een voordelige lening sluit u af via Lenen….

    Bereken snel en eenvoudig hoeveel geld u maximaal kunt lenen. Een korte samenvatting van de voor-en nadelen van verschillende leenvorme…

    Trackback by Geld Krediet — 10/20/2008 @ 1:27 pm