Geometry and the Holidays

The holidays are upon us, so of course it makes complete sense to look for geometrical connections. Or maybe that’s just me?

As a geometry teacher (just finishing up a Geometry & Spatial Reasoning course), I am seeing geometry connections everywhere. From the wrapped presents, to the origami ornaments, to the snowflake patterns, I am constantly looking for those real-world connections and easy (and cheap), ways to get students working hands-on with math.

We are all familiar with ‘holiday math’ problems that connect to wrapping presents – i.e. how much wrapping paper do you need, how much ribbon, etc. Area, surface area, linear length connections all very obvious. But, as a geometry teacher, I am also curious about the gift boxes themselves. I know it is often difficult to find 3D models for learning, so boxes provide a cheap way to provide students hands-on explorations of nets, area, surface area, volume. So –¬†teachers – get your students to bring in boxes after the holidays – so much you can do with these!!

Another thought – origami. This time of year, teachers often create holiday decorations with their students with paper-folding, which is fun, obviously, but can also be a great way to apply many math concepts. Shapes, fractions, and transformations for example. Take the following two origami designs – a star and a tree. As you are folding, you could be having students think about the individual shapes, but also the dimensions, the fractional parts after making a fold, what types of transformation have occurred – even congruence and corresponding parts.


For example, in the star above, after folds #1, what fraction of the square does each smaller square represent? When we fold that triangle in #2, what type of triangle is it? What fraction of the original square is represented in that yellow triangle?  What type of transformation does each fold represent? Are the triangles in #3 and #4 congruent? How do you know?

images (1)step-step-instructions-how-to-make-origami-christmas-tree-illustration-67138886

Again, looking at the tree folding above, what shapes do you see in #1? What fraction of the whole paper is each shape (so squares and triangles)? How about in #2? And which shapes are congruent? How do you know? Lots of great math, that you could really explore with students while they are also doing a fun hands-on activity.

Hopefully you can use some of these ideas with your students. Have a wonderful holiday season!!


Financial App (Pt 3 in series) – Let’s Talk About Money

pexels-photo-164501With the holiday season upon us, and people often spending beyond their means, it seems appropriate to continue the CG50 (and all Casio Graphing calculators) app exploration with the Financial App.

One thing we do not spend enough time on in K-12 education is financial literacy. I know there are some states that are trying to address this, but it is not enough. This lack of understanding about money, savings, taxes, interest, debt, etc. is a huge contributor to our enormous debt crisis. Take our current political focus on the ‘tax reform’ bill that’s up for a vote soon – most people do not understand the ramifications of this because they don’t really understand anything about finances and how taxes work. We do not in this country teach the basics of financial literacy, which is why we have so many people drowning in debt, losing their homes, barely surviving month-to-month on what they make, and forget about having the ability to save for the future. How many students really understand about saving money? Or how taxes impact their hourly wages (i.e. $10/hour is not that great when you factor in all the taxes taken out)? Or how not paying of your credit card monthly can make that $300 dollar purchase become a $400 or $500 dollar purchase?

When I taught in Virginia, they started a Personal Finance course ‘elective’ (only for stock-photo-working-coffee-phone-work-check-budget-finances-personal-finance-e841754e-765d-426e-af94-4b6a4ce9891fthose students technically not on the college prep track – which was silly, as ALL students should take a course on Personal Finance). I was lucky enough to be the pilot teacher in my school, so I could pretty much create the course. My goal was to help students understand the importance of financial planning so they could survive and thrive in the world, no matter where their path took them. We started with learning about different career options they were thinking of, and what a typical annual salary might be (so plumber, electrician, hair dresser, doctor, lawyer, teacher, etc). They learned to fill out job applications, and write resumes, and then we ‘pretended’ they had been hired and were receiving biweekly payments (I actually gave them ‘checks’). We learned about payments, investing, taxes, rent, credit cards, insurance, amortization,balancing a check book (the class had a ‘bank’), etc. They had to determine where they would live, whether they would get a car, how much they could spend on food, entertainment, etc. based on their salary. What they quickly learned is that their wages, after taxes, were often NOT enough to do much else – no fancy apartment and having to make tough choices (i.e. gas or food, no car, no expensive smartphone, taking bus, walking, no movies every week, no fast food, etc.) When a student comes to you all excited about their $9/hr job and all the things they will buy, and then realize after their first paycheck that it’s going to take months to have enough, it’s eye opening. And scary.

pexels-photo-164527What I learned is that we do not talk to students about real-world, practical mathematics enough –¬† simple things like saving money, calculating tips, balancing a checkbook, interest, credit card debt, etc. This is math they need in their everyday life. This is math that has purpose. This is math that will help them make smarter decisions about their future. Maybe if we did, we wouldn’t have so many people struggling to survive or believing every unrealistic promise they hear in the news..

My message – let’s get some Financial Literacy into K-12 mathematics programs!

With that said, here is a quick video on the Financial App that is available on the Casio graphing calculators. This video uses the CG50.