standard_description: Prove that, given a system of two equations in two variables, replacing one equation by the sum of that equation and a multiple of the other produces a system with the same solutions.
problem_activity: Narrative
The purpose of this activity is for students to write equations to represent the data they collected in Unit 1. Students can write any equation that makes sense to them.
This activity is intended to follow the last lesson of Unit 1. If that lesson was not completed, students can use sample data from the blackline master to complete this task.
When students use real-world data that they collect and determine ways of fitting their data into an existing mathematical model—put-together problems with unknowns in various positions—they model with mathematics (MP4).
To make this activity more challenging, students can share only their equation. Then their partner looks at the data and determines what story the writer intended to represent.
Required Materials
Materials to Gather
Materials from a previous lesson
Materials to Copy
Revisit Data
Required Preparation
Gather survey data from the last lesson in the previous unit, Animals in the Jungle.
Launch
Groups of 2
Give each group the data or posters from the previous unit or the sample data from the blackline master.
“Take a look at the work you did a few weeks ago. Review what you investigated and what you discovered.”
1 minute: quiet think time
“Discuss with a partner.”
2 minutes: partner discussion
Activity
Read the task statement.
5 minutes: independent work time
“Take turns telling your partner a story problem that matches the equations you wrote.”
5 minutes: partner discussion
Student Facing
Write at least 3 equations that match your survey data.
Student Response
Teachers with a valid work email address can
click here to register or sign in
for free access to Student Response.
Activity Synthesis
“What did you notice about making up a story problem for your equation? Were some easier than others? Why were they easier?”


aligns: no