## Real World Math in Proportional Reasoning and Linear Relations

Here’s a new Real World / 3 Act Math Task that is related to proportional reasoning and a direct variation linear relation with a partial variation sequel to boot!

Please note that this is **part one** of three tasks in a series:

- Stacking Paper – Direct Variation (y-intercept equal to 0)
- Stacking Paper Sequel – Partial Variation (y-intercept not equal to 0)
- Thick Stacks – Finding the Equation of a Line Given Two Points

## Act 1: What’s the Question?

Students watch the first video and begin discussing what the question will be:

How many packages of paper will it take for the stack to reach the ceiling?

Students can view the first video here:

Students then begin making their best guesses by using a “high/low” strategy to set boundaries for their best guess:

## Act 2: Reveal Some Required Information

Students can view the following video to gain some required information to help them solve the Stacking Paper 3 Act Math Task:

Alternatively, feel free to provide students with the following images:

## Act 3: Check Out The Solution!

Students can then view the solution here:

Or, you can simply share this photo.

## Discussion Prompts:

Assuming students use the given information and the assumption that the relationship is linear, they will come up with an answer of around 55 packages of paper. This is a great opportunity for classroom discussion around what could have gone wrong in this situation:

- Why was this not a perfectly linear pattern?
- What do you suppose happened to cause the pattern to vary slightly from the linear pattern?
- What sources of human error could have contributed to this?

Since we are stacking quite a bit of paper, students may realize that the weight will make the thickness or height of each stack near the bottom to decrease.

Something else to consider is the fact that the ceiling is made of ceiling tiles. It is possible that we could have popped out a tile in order to fit the last package.

## Sequel: Making Changes to Slope and Initial Value

In the original question, we are dealing with a proportion or linear relation of the direct variation type. Have your students consider what would happen in the following situations:

What would happen to the equation if we stacked the paper in the same room, but on this table instead of on the floor?

Explain how you got your new equation and then use it to determine how many packages of paper you’d need to reach the ceiling in this new situation.

What would happen to the equation if we stacked thicker packages of paper on the table in the same room?

Explain how you got your new equation and then use it to determine how many packages of paper you’d need to reach the ceiling in this new situation.

## Resources: Math Task Templates

Check out some resources to go along with this task.

### Stacking Paper Tasks Multi-Touch Book

Learn more about what’s in the multi-touch book here. Or, consider using the tasks in an interactive series of Google Sites pages.

### Latest Math Task Template

I designed this most recent version specifically for MFM1P Grade 9 Applied math, but it would also work well with MPM1D Grade 9 Academic and possibly grade 7/8 math:

### Previous Version

This previous version was created specifically with the Learning Goals from the MPM1D Grade 9 Academic Math course in mind:

## Stacking Paper Re-Makes

I love when people share remakes of a 3 act math task and encourage you to try it out for yourself! Once you start, you can’t stop!

Here’s one by Tim Boudreau from the Peel District School Board. Excited to see the rest of this roll out:

## Download All Videos & Resources

You can download all of the resources here.

How did it go in your class? Would love to hear about it!

## DOWNLOAD THE COMPLETE GUIDE

Take the learning with you by **downloading the complete guide** that you can save and print to share with colleagues during your next **professional learning community** meeting or for your own independent learning!

## Share With Your Tribe:

## About Kyle Pearce

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.

Access Other Real World Math Tasks

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