Lesson 13

In this lesson, students continue to reinforce the circle connecting three fundamental ideas: a solution to an equation is a number that makes the equation true, performing the same operation on each side of an equation maintains the equality in the equation, and therefore two equations related by such a move have the same solutions. In the warm-up, students are given an equation and then asked whether each of four other equations has the same solution as the given one. They see the move connecting each of the four to the original and conclude that they all have the same solutions. In the next activity, they compare two correct solution paths for an equation, and then two incorrect solution paths, identifying the mistakes made. Then they get some practice solving equations choosing their own paths.

Activity 4 Trading Moves is included here as an optional activity for students to practice building fluency solving equations with variables on each side. If using, print and cut up the Trading Moves blackline master. Students will need 1 set of cards for every 2 students.