# Unit 5 Linear Functions with Desmos

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I’m sure it has been done before, but here’s my take on teaching an entire unit using Desmos.  Before I begin, I’d be remiss if I didn’t share these articles.  Being completely transparent, I had this Desmos unit idea before my friend Turtle shared these articles with me.  Human Contact is Now a Luxury Good and How Busy Hands Can Alter Our Brain Chemistry a quick synopsis of the articles, working with your hands promotes happy brains and an increase in brain activity.  Too much screen time creates changes in the brain such as thinning and decreases the thinking and has been linked to depression.  Please take some time to read both of these articles.

With that said, my Desmos unit does not include an absence of peer to peer dialogue or teacher student conversations.

In the state of Georgia, 8th grade unit 5 covers linear functions.

Unit Suggested Timeline: 8 – 10 days

Suggested Sequence of Instruction:

1. Revisit graphs of proportional relationships. 8.EE.5 (To be taught concurrently with #2 and 3)
2. Connecting representations of proportional relationships. 8.EE.5 (To be taught concurrently with #1 and 3) (1 day)
3. Comparing features of different proportional relationships. Connect unit rate to slope through a context 8.EE.5 (1 day)
4. Use slope triangles to derive change in y over change in x. 8.EE.6 (1 day)
5. Derive the equation for slope intercept form, y =mx + b. 8.EE.6 (To be taught with #4)
6. Determine slope from a graph, table or linear equation. 8.EE.6 (3-4 days) (To be taught with #5)
7. Interpreting slope in context. 8.EE.6 (To be taught with #4-6)
8. Compare and contrast linear and nonlinear functions using tables, graphs and equations. (Emphasize y=mx + b as equation of a straight line) 8.F.3 (2 days)
9. Create examples and non-examples of linear equations. 8.F.3 (To be taught with #8)

Suggested Activities:

1. Click Battle  8.EE.5
2. Sugar Sugar  8.EE.5
3. Polygraph: Lines, Part 2  8.EE.6
4. Investigating Rate of Change  8.EE.6
5. Points on a Line– (with paper overlaps to create the similar triangles)  8.EE.6
6. Which is Steepest?  8.EE.6
7. Land the Plane  8.EE.6
8. Match My Line– (Slides 1 -7) 8.EE.6
9. Graphing Calculator with Lesson 13 from Illustrative Mathematics Open Up Resources  8.EE.6
10. Investigating T-Shirt Offers  8.EE.6
11. Charge!  8.EE.6
12. Graphing Calculator with Introduction to Linear Function from Illustrative Mathematics  8.F.3
13. Card Sort: Linear or Nonlinear  8.F.3

# Starting My Unit with Desmos

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One of my goals this year has been to establish a context for learning at the beginning of each unit (or subunit). In my district, unit 2 for Introduction to Algebra is Transformations. My 8th grade team decided to start with angles, which changed my plan a bit. Did I panic and complain?  Goodness no! (That was for all the Pete the Cat fans 😉). I went to Desmos and looked for a lesson on angles.

Day one of angles we went to the computer lab to partake in Lines, Transversals and Angles, which was my students’ first experience with Desmos and mine with a large group of students. They were so engaged and engrossed in the activity it was difficult to slow them enough to discuss the overlays used to explain placement of dots to identify congruent angles.

Over two days, students were able to make sense of angle relationships through the use of this activity and I had a Birdseye view of their thinking. I loved how the system captures the information for me to return to later. I used my formative assessment data collection sheet (not pictured) and recorded where individual students were based on the expectations of the learning target.

After this bit of exploration, I conducted guided instruction focusing on the characteristics students identified during the investigation. This was a great springboard into the angles discussion going from identifying angle pairs to using their characteristics to find missing angle measures and will now lead us into triangle measures.

This subunit included activities such as Transversals, Tape and Stickies, Angle pair flash cards, a word wall game called It’s on the Word Wall, a project and a formative assessment using Plickers. As we transition to triangles, I wish I had taken the time to return to this Desmos lesson and compare what students know and understand after looking at these concepts in different ways.
*It’s on the Word Wall rules can be found here