1. Compare Strategies Teacher Notes
You may want to make posters showing Marsha’s and Tara’s strategies to have them available for students to refer to during the discussion. (Student do not make these posters)
Strategy “Four Corners”: Post “Marsha”, “Tara”, “Both” and “Neither”. Asks students to vote with their feet. Go to the corner that represents who they agree with.
Vocabulary
equation
variable
©Algebra 1 by Southwest Washington Common Core Mathematics is licensed under a Creative Commons Attribution 4.0 International License

2. 2-7 Solving Equations With Algebra Tiles powerpoint
Practice Target
Practice 3: Construct viable arguments and critique the reasoning of others
Standard 2: Reason abstractly and quantitatively 2
©Algebra 1 by Southwest Washington Common Core Mathematics is licensed under a Creative Commons Attribution 4.0 International License

3. 2-7 Solving Equations With Algebra Tiles powerpoint
Learning Target
CF1b I can solve a 2-step equation.
What do you know about equations?
M1.1.B Solve problems that can be represented by linear functions, equations, and inequalities.
©Algebra 1 by Southwest Washington Common Core Mathematics is licensed under a Creative Commons Attribution 4.0 International License

4. Launch
Solve:
3x + 15 = 24
x = 3
Watch for how students do this. They might have been taught in previously to undo addition or subtraction first.
©Algebra 1 by Southwest Washington Common Core Mathematics is licensed under a Creative Commons Attribution 4.0 International License

5. Explore
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6. Marsha and Tara each solved the equation 3x + 15 = 24 differently.
Put the posters “Marsha”, “Tara”, “Both” and, “Neither” in the four corners of the room. Have students answer the question, “Who is correct” by going to the corner with their answer. This is the Four Corners strategy.
Who’s strategy is correct?
©Algebra 1 by Southwest Washington Common Core Mathematics is licensed under a Creative Commons Attribution 4.0 International License

7. Are both strategies correct? How do you know?
Marsha
3x + 15 = 24
3x = 9
x = 3
Tara
3x + 15 = 24
x + 5 = 8
x = 3
Lead a whole class discussion.
Have students explain each girl’s strategy.
Describe each girl’s strategy.
©Algebra 1 by Southwest Washington Common Core Mathematics is licensed under a Creative Commons Attribution 4.0 International License

8. Use both strategies to solve these problems.
2x – 8 = 14
5x + 7 = 42
x = 11
x = 5
©Algebra 1 by Southwest Washington Common Core Mathematics is licensed under a Creative Commons Attribution 4.0 International License

9. Debrief When is Marsha’s strategy better?
When is Tara’s strategy better?
©Algebra 1 by Southwest Washington Common Core Mathematics is licensed under a Creative Commons Attribution 4.0 International License

10. Rate your understanding of the target from 1 to 5.
2-7 Solving Equations With Algebra Tiles powerpoint
Learning Target 5 3 1 2 4
Did you hit the target? CF1b I can solve a 2-step equation with one variable.
Rate your understanding of the target from 1 to 5.
5 is a bulls eye!
©Algebra 1 by Southwest Washington Common Core Mathematics is licensed under a Creative Commons Attribution 4.0 International License

11. Ticket Out
Solve
5x + 15 = 50
x = 7
©Algebra 1 by Southwest Washington Common Core Mathematics is licensed under a Creative Commons Attribution 4.0 International License