Lesson 15

The purpose of this lesson is for students to solve story problems with unknowns in all positions using addition and subtraction. Students write equations to represent each story problem.

In the previous lesson, students matched story problems to equations.

In this lesson, students work in pairs to solve four different types of story problems and show their thinking using drawings, numbers, words, or equations. Students create visual representations of their thinking for one story problem and participate in a gallery walk in which they write equations to match other's representations and show how they made sense of each other's work. Throughout the lesson, students make connections between story problems, representations, and equations (MP2). 

Prior to this lesson, the teacher may consider reading Sadako and the Thousand Paper Cranes, by Eleanor Coer.

In this lesson, students made connections between story problems and different representations of their thinking, including equations. What questions did you ask to help make their connections more visible? What did these connections reveal about students’ understanding of different story problem types?