I did the lesson. They were super engaged. When they divided the price by the number of items they realized they did it incorrectly without me telling them. Great activity, thanks Dan!!

I had them do a 4 step writeup:
1) restate the problem
2) organize the facts and state how you will solve
3) solve it and show work
4) verify and check your work

In any case, we used your partial products as the opener one day earlier this week and every student in the class was engaged. Most found the unit rate for each and then the total. We had a great conversation about when to round. One 7th grade boy said that both answers were correct but leaving the entire decimal with the unit rate, then multiplying by however many items you are buying is the more accurate answer. Some kids were not happy with two correct answers. It was a great discussion about mathematics in the real world. Thanks for sharing all you do, it has certainly changed the way I teach.

Aren’t you just creating a contrived situation here? I’m with Dave on this one. While your photos might be good for provoking some questions about pricing strategies, I think a better motivational photo would be those supermarket ads where they advertise “3 for $5,” “buy two, get one free,” etc. This might provoke the same mathematical lesson, along with a valuable life lesson about the psychology of pricing.

1) I would rather see this problem as a comparison between price tags at two different stores that are both offering a “2 for $5” sale: one store that keeps that price for smaller quantities, and one store that doesn’t. (Around me, most grocery stores keep consistent and most convenience stores will have tags like “2 for $2 or 1 for $1.19”.) I feel like that’s a little less forced than a hypothetical situation about splitting.

2) Wasn’t sure whether to mention this, but it’s math-related and you always ask what questions we have after seeing your visual aids. My first question was “What’s the pattern/rule behind the letter omissions on the price tags?”. My answer is that there doesn’t seem to be one; the full, unaltered phrase “APPLE JUICE” would fit numerically and width-wise in the space used for “BLKBRRY SODA”.