The DoughRoller Weekly RoundUp (Mathematics Phone Number Edition)


Everyone once in a while, I like to have fun with mathematics.  For those wondering if this is even possible, I assure you it is.  You see, mathematics is like no other subject you learn at school.  There is no interpretation and you’re answer is either right, or wrong.  No in-between.

So today, let’s see if we can have some fun with phone numbers. Humor me, and perform the following steps

  1. Find a calculator and type in the first three digits of your phone number.  Don’t include the area code here … we’re only talking about 7 digit phone numbers.
  2. Multiply that number by 80
  3. Add 1
  4. Multiply the new number by 250
  5. Now add the last four digits of your phone number
  6. Go ahead and add those same four digits one more time
  7. Subtract 250
  8. Then divide the number by two

What’s left … we’ll if you did it correctly, you should see your seven digit phone number.  Unfortunately, this is one of those tricks that you won’t be able to do in your mind, so it’s somewhat less cool an effective than others.  However, it’s still pretty awesome that these rules work no matter what your phone number is (forgetting 000-0000).  Who thinks up these things?

Now time to check out the best money articles from this past week.

10 Cheap and Creative Halloween Costumes of 2010 @ PT Money: The last time I dressed up for Halloween was 2004 when my friends and I went as Power Rangers (I was the green/white one).  Anyway, we arrived at our destination only to find another group of Power Rangers and things got very ugly.  Too true to be made up.

Do You Have To Pay Taxes on Unemployment Benefits @ Cash Money Life: As a general rule of thumb, if you make money, you owe taxes! For a clearer answer to the question asked, follow-through the link.

Are There Any Safe Investments Left @ Mainstreet: Unless you’re investing your money in an FDIC insured savings or checking account (CD’s too), there are few true investments you can call “safe”.  This article will gladly point you in their direction.

10 Ways To Lower Your Cost of Living @ Free From Broke: One of the easy ways I found to reduce my cost of living was reducing our family to one car.  Working from home made that an easy decision but for those in more complicated situations, perhaps a carpool is the way to go.

15 Tips To Save Money on Vacation @ Sweating the Big Stuff: Vacations are tough to swallow sometimes because after you come home, you have nothing tangible (other than pictures and memories) to show for the massive amount of money you’ve spent.  Read on to find 15 great ways to lessen that money spent.

Tips to Get the Most Out of Your Paycheck @ One Money Design: If you’re one of the millions of Americans living paycheck to paycheck, read up on how you might be able to extend your check a little further.

Wedding Taxes: Four Must-Know Tax Facts For Planning Your Big Day @ Money Under 30: Weddings can eat up an entire year’s worth (or more) of salary so make sure when you plan your next wedding (and hopefully your last), you take advantage of the tax breaks offered.

Published or Updated: December 17, 2011


  1. Craig says:

    Thanks for the mention!

  2. Ryan says:

    Fun number trick. Thanks for the mention. :)

    By the way I checked out Get Currency – good stuff!

  3. j says:

    uhm, no duh it works every time.
    Any 3-digit number that does all of these steps (minus adding the last 4 digits twice) equals that number, plus extra 0′s at the end.
    “# Add 1
    # Multiply the new number by 250
    # Subtract 250″
    So, basically the first an last step of these three cancel each other, because 1×250=250, 250-250=0.

    # Multiply that number by 80
    # Multiply the new number by 250
    # Then divide the number by two
    80×250=20,000. Divide by 2, it is 10,000.
    So you are just multiplying your first 3 #’s by 10,000, and adding 2xlast 4 digits then dividing by 2 is the same exact thing as simply adding the numbers once.

    So no duh, you multiply 123 by 10k, you’ll get 1,230,000 or 123-0000, you add the last 4 digits of your phone number (1234) and you get 123-1234. Calling this process “awesome” makes me not trust your financial advice at all, because if you can’t look at math like this elementary stuff and see that it is not some “trick” but just managing to add enough steps to make it LOOK like one, then how can you manage concepts like complex interest?

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