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# Fast Clapper

## Using Real World Rates and Proportional Reasoning

The following 3 act math task shared by Nathan Kraft (@nathankraft1) involves proportional reasoning with opportunities to address learning goals around rates, proportions, rates of change and creating equations.

Jon Orr and I have used this task in presentations a number of times over the past few months and many have asked us to share our slide deck and other resources with a summary. So, here we go!

## Act 1 – Sparking Curiosity

Show the following video:

*Note that this is an edited version of Nathan’s video where I have blacked out the number of claps. You can always add. You can’t subtract.

I typically give students a prompt to jot down what they notice or wonder. Giving a minute of rapid writing in point form or otherwise can be a great opportunity for students to get sucked into the problem.

Students might notice:

• A timer
• he claps fast
• we saw about 4.5 seconds worth of clapping
• current world record was 721 claps in a minute
• …and so on

Students might wonder:

• Why is he clapping?
• are those “legal” claps for a world record?
• how many years of practice does he have?
• will he break the record for claps in a minute?
• …and so on

While we will engage in a healthy amount of discourse around these noticings and wonderings, my main focus is to pull out the question:

Will he beat the current record?

I’m then going to ask students to make a prediction. Will he beat the record? How many claps per minute do you think he’s going to get based on what you saw? I might even show the Act 1 Video a few more times to give students an opportunity to use a mathematical strategy to help with their prediction.

We will record student predictions up on the board next to their names for an opportunity to celebrate later.

## Act 2 – Climax: Raising the Tension

Show Nathan’s video:

I am very explicit with my words after showing the video. I say something like:

Do you think you can improve your prediction?

The reason I do this is so that every student has an entry point to the problem. I don’t necessarily care about the exact answer the “math” says you should get. I’m happy with a student using friendly numbers to help them get closer. I’m happy with students using some sort of strategy we might have seen in the past (proportions or maybe trying to create an equation from previous years). The best part by doing this is everyone can get closer to the expected actual result.

What do you think? Will he beat the record?

Here’s one question from a Knowledgehook Gameshow that could be used to support this task:

## Act 3 – Conclusion: What Really Happened?

Allow students to check their solutions:

How are you using the problem? Please share in the comments and be sure to thank Nathan for sharing on his blog or on Twitter.

## New to Using 3 Act Math Tasks?

Download the 2-page printable 3 Act Math Tip Sheet to ensure that you have the best start to your journey using 3 Act math Tasks to spark curiosity and fuel sense making in your math classroom!

## Share With Your Learning Community:

I’m Kyle Pearce and I am a former high school math teacher. I’m now the K-12 Mathematics Consultant with the Greater Essex County District School Board, where I uncover creative ways to spark curiosity and fuel sense making in mathematics. Read more.

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Spark Curiosity!