## Pages

### Learning about Domain and Range

If you're coming here from my Domain and Range Intervention post, the blue graph cards helped a whole lot! In this post are more ideas for teaching the topic and what has worked in my class (after we get over the initial hump!)

When first introducing the topic of domain and range, I always get a lot of blank stares. I get a lot of x values for range and y values for domain. I get a lot of domain intervals heading from infinity to negative infinity.

Each year, I add more and more to this unit, filling in the gaps from the year before, and this year is already shaping up to be no different. This week I decided to add a quick [hand-drawn] sorting activity to solidify domain.

The activity was super quick for some students but took 15 minutes for others. Please excuse the hand-drawn graphs. I'm a little ashamed! You can also make fancier graphs in Graph Free.

Every year, I love listening to my students to see where their misconceptions are. More often than not, their misconceptions are completely fascinating.

One girl became very confused that, in the above graph, the domain went to positive infinity but the range came from negative infinity! And I see her point! I mean, the arrows are pointing down. We take a quick look at range in the stock market, which helps. This lead to a great discussion about the right arrow pointing down AND right.

 Domain and range of graphs video

Above is a video showing how to find domain and range of graphs using a pencil (or pen in my case). The graph with the red arrows and the practice cards I'm using can be found here and here

Once most of my students start to feel comfortable with finding domain and range, we do a matching activity. I really like matching activities because there is a finite set of answers. I give students this domain and range matching activity

After matching all of the domain and range slips onto their cards, my students sort their cards into 2 piles - function or not a function. This acts as a good review of our previous unit on functions. It's fun watching them work together to figure it all out.

I don't like giving quizzes, which I know is controversial! My students are super anxious from years of failure and I just don't feel right about perpetuating it.

When I do give quizzes, they are always open-notebook. For many students, Algebra 2 is their last public school math class. I want my students to leave high school with a good feeling about math so that they are more likely to go on to take more courses.

Instead of a quiz, we complete a domain and range scavenger hunt to sum up understanding.

This discounted includes the matching activity and scavenger hunt seen in this post as well as a domain and range math pennant.

 Algebra Activities Bundle

Browse all algebra activities.