Another quick post to catch up on a problem-based lesson from the other week. This one was co-planned & co-taught with my student teacher, Nicole Darling.

We made up a problem to do with selling t-shirts, comparing costs & number of shirts in order to teach the elimination method of solving linear systems.

We posed the problem:

Your class is trying to raise money through selling t-shirts. There is a $150.00 set-up charge and each t-shirt costs $4.00 to make. You will be able to sell your t-shirts for $10.00.

**What questions can we ask?** Sample responses:

**Estimate** how many shirts you would need to sell in order to break even:

**Solve**: A few (but not all) of their boards:

Most groups solved using a table or just by calculating the 150$ debt divided by the 6$ profit on each shirt to find 25 t-shirts. One group actually did substitution all on their own. Ms. Darling then did some direct teaching on the substitution method w/ the class as a whole & sent them back to their boards to check their answer using this method.

Interactive Pear Deck slide deck available here.

– Laura Wheeler (Teacher @ Ridgemont High School, OCDSB; Ottawa, ON)