One of my frustrations with being a math teacher was having people tell me they couldn’t do math.

It wasn’t just the kids, either. It ranged across a wide variety of adults as well.

One of the things I taught my seniors is that some people rely on the fact that they’re either scared of math, or think they can’t do it. You can’t do math? Well, you will probably be screwed over on your paycheck or loans or something else.

An example: I recently sat through a free webinar. It contained information I wanted, but at the same time was a selling platform for another (paid) course.

The course itself was $497. That price tag is enough for most people to say, “well, that’s a lot of money. I can’t afford it.”

The author offered a payment plan so that you could split the payment over three months. Three months of $198.

I looked at those numbers, not because I was interested in coughing up the dough. I looked at them because of the fact that they author was trying to take advantage of the fact that most people won’t (or can’t) do the math.

So let’s do it together:

The total cost for the single payment: $497.

The total cost for the 3 monthly payments: 3 * $198 = $594.

So the total cost of spreading those payments over 3 months, or 1/4 of a year, is $594-$497, or $97.

Let’s look at the interest rates:

The simple interest rate is calculated as the amount of interest divided by the product of the principal times the time period. In our case, the amount of interest is $97. The principal would be what you would have spent on it if you paid it right away, or $497. The amount of time is three months, or 1/4 of a year.

So as you can see, the annual interest rate on this is a whopping 78%.

Wow.

The author is counting on you not being able to do that math.

And it’s not just sneaky salesmen on the web that do it either.

My Girl Scouts learned a lesson in marketing during our cookie booths. Cookie prices have hit $4 a box in our area. $4 for one box, $8 for two, $12 for three, $16 for four, $20 for five. Straight up multiplication.

But when my girls put “5 for $20” on a sign, people started buying 5 boxes of cookies at a time. *Because the customers perceived it as a deal.*

Some of the customers caught on. And they laughed with us. But most of them didn’t. They went away thinking they got bargain prices for buying in bulk.

I am convinced that more and more not being able to do simple math is just a way to get screwed over.

And it’s not like you can’t get help. You need to know what interest you’re paying? Google it! Can’t remember how to do compound interest? Google it! Need to figure out where something is going to land? Google it! Need to calculate an irregular area? Google it! In fact, I told my seniors that I wasn’t going to make them memorize formulas. “Why?,” they asked. “Because when you are in the real world, and you need to do this, you’re going to go to internet for help.

There is no excuse not to do the basic math anymore. With Google available on just about everything now, we need to learn how to take back our math.

Not everyone is cut out to do calculus. But everyone should be able to do enough “figgerin'” (as my grandfather would say) to keep people from taking advantage.

Including the Girl Scouts.

Photo by PinkMoose