This is the flipside of

5 Math Topics I'm Bored With. These are topics I love to teach for various reasons, and believe these are generally underused topics. Many are casualties of our standardized curricula.

**5) Cake Cutting**
Fair division problems are the coolest! If you've never studied cake cutting beyond "I cut, you choose," you really need to because it's an absolute treat (pun intended). Life can be fair, you just need to learn the mathematics behind it. And it gets pretty intense once you move beyond 2 or 3 participants. People from

Edina love this one!

**4) Partial Fractions**
OK, this is probably the most boring on this list. But partial fractions is an activity that gets pretty intense algebraically, and the level of that intensity is not overwhelming. Partial fractions force you to factor polynomials and set up & solve systems of equations. On one hand it's just another process, but on the other, it's an algebraically rich topic. (By the way, I almost put conic sections here...also another nice topic that reinforces completing the square.)

**3) Truth Tables**
My 8th grade math teacher's name was Gerry Warkel. Best math teacher I've ever had

__in my life__. Mr. Warkel started off our 8th Algebra class with truth tables and other logical ideas like the

square of opposition. Although this didn't have direct application to the other things we did in Algebra 1, it got the juices in our brains flowing and I really do believe the foundation of logical reasoning made a big difference throughout the course. Plus, this is another topic that is fits well into almost any high school math class.

**2) Combinatorics**
In high school we don't go much beyond a question like, "how many ways can we form an 8-person committee" types of problems. But you don't have to dig all that much deeper to get into some really cool conceptual mathematics.

My personal favorite goes something like, "Ten people are ordering ice cream cones and they each have a choice between vanilla, chocolate, or strawberry. How many different possible ice cream orders are there?"

*Spoiler alert: *the answer involves filling 12 spaces with 10 stars and 2 bars:

* * | * * * * * * * | *

- - - - - - - - - - - -

So you *partition* the ten orders into the three flavors (in this example, 2 vanillas, 7 chocolates, and 1 strawberry), and your answer turns out to be

where *n* is the number of choices that need to be made and *k *is the number of possible choices.

For me, it doesn't get any more fun than that!!! And there's plenty more where that comes from. Combinatorics are a super-rich, under-utilized branch of mathematics.

**1) Financial Math**
I am trying to restrain myself here but I'll warn you I get pretty fired up about this one. Why don't we teach the mathematics of investments, loans, mortgages and credit cards? Is there anything more directly applicable to LIFE than this? So why don't we teach it?

**Because it's not on the effing test, that's why**. I don't know who this idiot is who decided this wasn't important, but someone did, probably because we are trying to get every kid "college-ready," forgetting that "life-readiness" is what should be

*most *important.

Now that I'm firmly on my soapbox, let me be a little more specific. Our kids do, for the most part, learn about compound interest through

*Pe*^{rt}. But these problems have a very superficial context, and if we dug just

*a little *deeper, we could teach kids how to make

*life choices* based on a deeper understanding of the mathematics. For crying out loud, these kind of choices are

only a click away.

Or take mortgages. How many of us really knew how the hell to buy a house before we did it the first time? Did you know what was involved in the closing costs and if it would be better to roll them into the loan or pay for them outright? Did you know what points were? When we buy a house, we are told a monthly payment, and we might even break it down by principle vs. interest. But do we create the amortization schedule? How much more interest would we pay over time if we did a 20-year loan vs. 30? And you might pay more interest, but how will inflation affect the actual buying power that money will have in 20 years?

How about cars? Will it be

better to lease or own, and if we buy should we take the low APR or the cash back?

Shoot, we should be all strung up for educational malpractice for not helping kids understand student loans at even the most basic level!

But the big one is

**credit cards**. Most credit cards calculate a monthly interest based on something they call

*average daily balance*. The mathematics behind ADB are pretty straightforward. Yet, I'll venture to guess that most MATH TEACHERS don't even know what this is or how cards calculate it. There's a shitload of math

on the back of every credit card solicitation, and if we take a day, yeah ONE DAY, to simply explain to the kids what all of those rates mean, I'm telling you we could make a difference in their lives far beyond any impact we could make teaching some more abstract branch within our field.

But sadly, I don't have time for this, and neither do you. Someone decided it was more important to make sure students can prove that (

*x*^{2} +

*y*^{2})

^{2} = (

*x*^{2} –

*y*^{2})

^{2} + (2

*xy*)

^{2} can be used to generate Pythagorean triples (

common core, page 64).