Lesson 12

The purpose of this lesson is for students to solve Compare story problems about measurement.

In the previous lesson, students solved Compare, Difference Unknown story problems about length measurements. Students used connecting cubes, drawings, numbers, words, or equations to solve and represent these problems. They discussed how some problems can be solved using either addition or subtraction.

In this lesson, students solve two new problem types, Compare, Bigger Unknown and Compare, Smaller Unknown, through the context of measurement and consider how a representation can be used to solve different story problems. Due to language demands of these types of problems, students will focus on Bigger Unknown versions with “more” and Smaller Unknown versions with “fewer.” Students are reintroduced to a diagram that may be helpful for Compare problems and prepares them for working with tape diagrams in grade 2.

• Create a poster for the Lesson Synthesis with the problems from Activity 1 and Activity 2 and this unlabeled diagram shown two times:

  

  

Put each gameboard in a sheet protector.

How did the Three Reads routine support your students in making sense of a story problem? What can you do to encourage students to use this method for themselves to make sense of a problem?