This post provides details for a discovery activity for intercepts. Students shop for tacos and burritos at Taco Bell. They are to find combinations of number of tacos and number of burritos. This will include no tacos or no burritos. The activity is provided on a Google Doc.
Student prior knowledge is leveraged to provide a meaning making activity. The concept of intercepts is developed through 0 tacos or 0 burritos. Here are the steps for the activity.
The students are tasked with spending the entire balance of the $30 in gift cards on tacos and burritos.
They are to find all the combinations that are possible.
Students enter the combinations into a table found on a linked graph on Desmos. The image below shows the final product, upon completion.
Then they are tasked to identify the two combinations that standout in the table.
Finally, they unpack why these two combinations are unique in the graph.
At that point, the teacher can present the “mathy” term, intercepts.
Below are images of a Google Doc with the activity. You have to make a copy to edit it. Here is the link to the Demos graph with blank table and labeled axes. It is included in the Google Doc.
Simplifying expressions (see photo below) is one of the most challenging algebra tasks for many students receiving special education services. A major problem is that it is typically presented as symbol manipulation…addressed in very symbolic form.
My approach is to make math relevant and more concrete. Below is a scaffolded handout I use to help unpack the concept. In the handout I start with items the student intuitively understands, tacos and burritos or tacos and dollar bills. In the top left of this handout the student is asked how many tacos he or she has. 3 tacos eventually is written as 3T. See next photo to see how the handout is completed as NOTES for the students.
As I work with the problems below I remind the student that the “T” stands for taco so “3T” stands for 3 tacos. This takes the student back to a more concrete understanding of what the symbols mean.
To address negatives I use photos of eating a taco or burrito. “-2T” is eating 2 tacos.
So “3T – 2T” means I have 3 tacos and ate 2. I have 1 taco left… 1T. For students who may need an even more concrete representation, use actual tacos or other edible items.