Sweet Snacks: A video and concept by Andrew Stadel, customized by Dr. Polak!

I spend a big chunk of my weekends in search of grand lesson ideas. My summers are also preoccupied with this obsession, but the problem with the summer is that I have to wait so long to actually use the lessons I discover, I often forget that I found them. It is not that I am disorganized; my organization skills are pretty top notch. However, that old saying if you don’t use it, you lose it, applies to me in this situation.

One of those lessons I found (was unable to use immediately) and then promptly forgot about was Robert Kaplinsky’s calorie lesson for inequalities. This was serendipitous because this year, as I was hopelessly searching, tweeting, i.e. begging for inequality inspiration, I had come across a three act math lesson called *Sweet Snacks* by Andrew Stadel. After tweeting him for some guidance with his lesson, he promptly tried to sway me away from his and towards Kaplinsky’s calorie lesson as Kaplinsky’s lesson was superior in Stadel’s opinion. His tweet reminded me that I had found and planned to use Kaplinsky’s lesson, but I saw something spectacular in the Sweet Snacks lesson as well. I am so happy that I found a way to use them both!

I utilized Kaplinky’s lesson for equations instead of inequalities (see previous blog post for details), and I then got to work to customize Stadel’s Sweet Snacks. I started the lesson with my class by telling them that I was going to share a short video with them of a math teacher hero of mine named Mr. Stadel. They were instructed to think about any questions that came to mind and anything in particular they wondered about. Of course, we would discuss immediately following the video.

As this is a three act math lesson, the first act involved Stadel’s son sitting in a shopping cart as Stadel pulled 8 boxes of Teddy Grahams into the cart. The video then switched to Stadel pulling 8 bags of “Circus Animals” (Animal crackers,) into the cart. The video zooms in closely on the young boy in the cart as he pulls out a 20 dollar bill out of a wallet. The wallet clearly has no additional cash.

My students wanted to know why anyone would buy so many boxes of snacks , how much did each box cost, what the two Teddy Graham flavors were, and whether $20 was enough for all of the sweet snacks in the shopping cart (JACKPOT). Of course, off topic but hilarious and worth a share in my opinion, was “wondering” why a cut out statue of Guy Fieri appeared in the video and whether or not his hair was ridiculous.

I asked them what kind of information could help them with the math questions. Students quickly agreed they needed to know the prices of the sweet snacks. And with that, I shared Act 2.

It was immediately revealed that the Teddy Grahams were $2.49, while the price of Circus Animals was $3.49 .The students asked me to rewind the video several times so they could count how many bags of each were put in the cart. It was obvious to them quite quickly that $20 was not enough money. Mr. Stadel could only purchase items that were $20 or less. I was silently cheering my students’ recognition of the inequality example without me needing to articulate its existence in a direct instruction type of way.

This is where I prompted students to translate the scenario into an algebraic inequality. Students had already solved basic procedural inequality problems in the previous lesson. Sweet Snacks, provided a context for the types of examples they had seen. They were all sure that Mr. Stadel could not afford all of the bags of Teddy Grahams and Circus Animals with only $20, so I asked them to write the math language to demonstrate that fact. It was not easy for them, but eventually, students came up with: 8($2.49+$3.49)=$47.84 >$20

The next question, naturally, was, what are the combinations of sweet snacks he __can __afford? Students were instructed to write an algebraic inequality using the prices given of Teddy Grahams and Circus Animals. They had the option to write an inequality with one sweet treat or both sweet treats. In addition to writing the inequality, they were asked to solve it and graph all the results. If able to finish quickly, they were asked to write a second or third alternative algebraic inequality and/or help out a neighbor.

When we shared out and compared, we talked about the constraints of budgets. Every household has one, even if students were not privy to the information that gave details about the restraints their parents must use to control their purchases. We all have to stay within the range of some sort of budget. Do not spend more than x amount; do not let your bank account fall below x amount. This is life for all of us!

They had calculated combinations of sweet treats that were possible to purchase with $20 and possible combinations that would have exceeded the $20 within this short amount of time.

Keeping this in mind, I asked students to write an inequality to represent how many Teddy Grahams Mr. Stadel would be able to purchase if he had $20, but also had to pay an additional 6.33% sales tax on his total purchase. Sometimes there is tax on snacks, depending on where you live. This was another off topic, but interesting conversation from the perspective of 7^{th} graders. Believe me, I could write a separate blog on off topic comments. This is not that blog! Once again, they were asked to write, solve and graph their results.

In the next scenario, I presented a circumstance where there was no tax on this type of food. So obviously, a new algebraic inequality needed to be written, but I didn’t stop there…Students were asked to write an algebraic inequality to represent the Teddy Grahams Mr. Stadel would be able to purchase if he had $50 (woohoo, more money), AND had a 20% coupon off the price of his total purchase. They did great with synthesizing all of the different math concepts in this particular problem.

At this point, I was convinced students were more than ready for the manufactured inequality problems from our textbook and they proved my hypothesis quickly. Let’s be honest, textbook questions are about a dime a dozen, but they do serve a purpose. The problem with most textbook lesson ideas is that they offer instructional inspiration at a very superficial level. That is why I am always in search of a way to bring the level of instruction to a deeper and more meaningful place with my students. This, of course, is why I continue to be an enormous fan of Andrew Stadel, Robert Kaplinsky, Dan Meyer, and the magnificent math community that allows me to become a better teacher every day.

Thanks you for posting this. I’m so glad it went well for you and your students. If ever presented with the opportunity, I’ll give this task another chance. I like the how you included taxes and the extension you tweeted with the coupon. Keep up the great work!

Have fun with this little desmos representation.

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https://www.desmos.com/calculator/uskosazm2h

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