I continue to be surprised at how much of a challenge computing percent discount is for students. It’s prior knowledge. If you ask them to explain what a discount is in their own words you’ll get a response like “it makes something cost less.” The students may even have mastery of computing a percent of a number. I believe that in part this is a working memory issue – extra step to process is a little too much.
The photo shows a scaffolded handout (links below) I created to help with the conceptual development of the steps for computing the new, discounted price along with the actual mathematical steps. In another post I showed the use of ten-dollar bills to conceptualize percents. This handout builds on that activity and the scaffolding makes it easier for the students to access the concept. The students have an item that costs $250 and is on sale for 60% off (allows for nice “round” numbers). The students cut out the discount and have the new price in their hand. When a student has trouble with the mathematical steps at the bottom of the page I review the act of cutting to help with concrete understanding.
On a follow-up pop quiz the vast majority of students were able to compute the new discounted price.
money handout (print in black and white per legal restrictions)