52 Card Pickup?

Act 1:

How many cards did he drop?

I accidentally dropped a bunch of cards while shuffling a deck one day, and a 3 act idea followed.

Update: I’d start the class with Estimation 180 Day 4 because Robert Kaplinsky made a good point. Will the students ask for the information I’m providing in Act 2? If not, how can we lead them there? The lamppost estimation could get the kids into the needed mindset.

Act 2:

What information would be useful to figure this out?

A couple sources inspired this task. First, Robert Kaplinsky via Open Middle.

Open Middle Number Line

Second, Malcolm Swan via a Dan Meyer tweet.

Malcom Swan Number Line

With these in mind, I thought it would be neat for the students to estimate what fraction of the deck was dropped with the following image.

Stack Height Estimate

From there, they could use the estimate to make a calculation. I’m excited about the possibility of multiple methods including some great visuals.

By the way, the students need to know how many cards make up a full deck. No tricks here.

Full Deck

After the class works for a while and students are given the opportunity to demonstrate their thought process, the kids can go back and test their work with the actual dimensions.

Stack Height Actual

Act 3:

Official Lesson Page:


  • Common Core
    • 3.NF.A.2 – Understand a fraction as a number on the number line; represent fractions on a number line diagram.
    • 4.NF.B.4 – Apply and extend previous understandings of multiplication to multiply a fraction by a whole number.
  • TEKS (2015-2016)
    • 3.3(A) – represent fractions greater than zero and less than or equal to one with denominators of 2, 3, 4, 6, and 8 using concrete objects and pictorial models, including strip diagrams and number lines
    • 5.3(I) – represent and solve multiplication of a whole number and a fraction that refers to the same whole using objects and pictorial models, including area models

    How can this task be improved? Did I choose the best fraction for the estimate image?

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