Saturday, April 12, 2008
Deconstructing "magic math" emails
We've all gotten them at some point or another. These emails promise to figure out some magic secret number you have in mind, and after a really long process of "subtract this" and "multiply this," bam! Magic number. And you're like "Howdee do dat?"

It doesn't take a rocket scientist to figure out that these emails are just really long, streched out algebraic equations. Still, I was bored today and I decided to indulge my nerd side a little bit. Pagbigyan niyo na, Nerd Me doesn't come out very often because she's usually overshadowed by Bumbling Idiot Me.

Let's take, for example, an email that I got from my dad last week:

1. Pick the number of times a week that you would like to go out to eat. (more than once but less than 10)

2. Multiply this number by 2 (just to be bold).

3. Add 5.

4. Multiply it by 50.

5. If you have already had your birthday this year add 1758. If you haven't, add 1757.

6. Now subtract the four digit year that you were born.

7. You should have a three-digit number.

The first digit of this was your original number. (i.e., How many times you want to go out to restaurants in a week.)

The next two numbers are ...

YOUR AGE! (Oh YES, it is!)

THIS IS THE ONLY YEAR (2008) IT WILL EVER WORK, SO SPREAD IT AROUND WHILE IT LASTS

OMG MAGIC. Aaaanyway, all it takes is a little patience, and you'll be able to work out the algebra behind it. In about ten minutes, I came up with this:

Equation:

assume that you have already had your birthday this year (if not, change 1758 to 1757)
x is the number of times you'd like to go out to eat
y is the year you were born

50(2x + 5) + 1758 - y = 100x + 2008 - y

The left side is the step-by-step equation as written in the instructions. The right side is what the outcome should look like -- the number (which is multiplied by 100 since it's in the hundreds place) plus your age. For example, I picked 5 and I'm 18, so 100(5) + (2008 - 1989) = 518.

Now, let's simplify!

50(2x + 5) + 1758 - y = 100x + 2008 - y
100x + 250 + 1758 - y = 100x + 2008 - y
100x + 2008 - y = 100x + 2008 - y

There, now identical on both sides.

It is true that this particular one only works for 2008, but all you need to do is add 1 for every succeeding year, and the formula would still work. It's just year-specific, is all.

You can even use algebra to figure out the secrets behind some card tricks. So, the next time you get one of this emails, you don't have to be like "Howdee do dat?" Just say, "Nyeh." :P
JC got bored @ 9:00 PM

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