# Piggy Bank problem #MPM2D

I’m trying to blog more about my lessons/activities/problems this year. Today’s is more of a problem-based learning approach I guess. My goal was to review solving systems graphically with my grade 10 academic students.

I made up a problem about Lisa & Bart saving money in their piggy banks:

Lisa puts \$3 in her piggy bank each week. She has a total of \$19 in it as of today.
Bart puts \$1 in his piggy bank each week. He has a total of \$9 in it as of today.

What questions could we ask & solve? Some sample responses:

When do they have the same amount of money in their piggy banks?

Estimate:

Solve:

Everybody used a table. I forgot to take photos of each board, but most groups answered that they will never have the same amount of money. Two groups worked their tables backwards to include negative numbers of weeks (before today). I then asked them to write an equation for Bart & Lisa each which we then graphed using a Pear Deck drawing slide.
Here’s a summary of our work:

Pear Deck interactive slide deck available here.

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