How much will my Pizza cost?

101qs lesson | PowerPoint lesson

You know you’re a Maths teacher when you go out to a restaurant and upon deciding whether you want the big or the really big pizza, you notice that the price increments aren’t consistent. Then it made me think, why are pizza prices based on the diameter of the pizza pan? As I’ve been doing a lot lately, when ever I want to know the answer to something even slightly mathematical, I create a lesson for my students to figure it out for me.

Act One

Ask the students to, without talking or thinking too long, write down the first question that comes to their mind?Act1-1 From the menu, pick a type of pizza Write down the Pizza name and the 12” price Why did you pick that one?

  • Flavour
  • Price
  • Value for money
  • Novelty
  • Trying something new
  • Other?

How much will the 18″ pizza cost?

Act 2-1 Write down what you would pay for an 18” pizza Have a guess at how much it costs (they may be the same) Their guess: Hopefully, your students made complete guesses. Why do you think that you guessed that price? What affects your opinion / “gut instinct”? Was it a reasonable guess? Would you pay that amount?

Act Two

What else do we need? What information do we have? What information do we need? How would we use this information?

Then, show them some more information…

Act 2

Then, ask questions like:

Did the 15” pizza price make you rethink your original guess of the 18” price? How much more expensive was the 15” pizza price than the 12”? If you feel differently, write down your new guess for the 18” price. If the students are in table groups, give them 5 minutes to calculate the price of an 18″ pizza After the 5 minutes, students share their methods with their table group. These are then shared amongst the class through a discussion. What’s fair? Students are to consider their answers by answering the following questions: Is your price fair? What would be a “fair price” to pay? How do restaurants normally price their pizzas? What else needs to be considered apart from the diameter of the pizza?

Act Three

The Answer

Act 3-1


Pricing pizza mathematically How can we recreate the menu to be mathematically fair? How might the prices be determined? In table groups, students are to pick one type of pizza. They then come up with a “mathematically fair” price for the 12″ and 18″ pizzas based on the 15″ menu price. Students are then asked to answer the following questions: How close was your answer? What is more “value for money”?

  • The original menu
  • The Mathematically fair menu

Why? Then, the teacher shows how to find the area of the pizza and calculate the prices based on the square inch price of the 15″ menu price. Students then recalculate their answers from the previous section.

How much did this pizza cost?


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