Teaching Range with the Stock Market

Every year in Algebra 2 we start off with a review of linear equations, move into function vs. not a function then into domain and range. This year I have a tiny Algebra 2 class of all boys who, as I quickly found out, are pretty interested in the stock market. 

I find with anything involving review, my students check out. Since domain and range are taught in 9th grade now, seeing it again in 11th grade Algebra 2 can feel like a review at first, especially during (re)introduction. Lots of blank stares.

So I pulled up Facebook's stock chart and we looked at the day's range of... price! 

We talked about how days are a measure of time, which is always on the x axis (domain) so price would be found on the y axis (range). I pointed to our math word wall a lot to remind everyone which is domain and which is range. 

We then got into talking about share prices and how much money people can make in the stock market. You know, the good stuff that has nothing to do with domain and range! 

But I do think that taking a step back to build context is important. It builds engagement, which gets kids wanting to move forward. 

Range always seems to be a bit trickier for my students than domain, so linking it to the stock market really seemed to help.

The Math Dyal: Connecting Inequalities to Domain and Range

My friend at The Math Dyal wrote a great blog post about how she introduces domain and range in her Algebra 1 classes. Mandy teaches younger kids so uses inequality notation instead of the interval notation we use in Algebra 2. 

My students always need extra practice finding the domain and range of graphs, so I made them this set of domain and range practice cards (free). We use them before moving into our assessment activities. 

More domain and range blog posts:

Domain and Range Intervention!

Learning About Domain and Range