Lesson 17

The purpose of this lesson is for students to use their understanding of addition and subtraction to solve Compare story problems.

This lesson is optional because it does not address any new mathematical content standards. This lesson does provide students with an opportunity to apply precursor skills of mathematical modeling. In this lesson, students make origami tulips and puppies and use problem sentence frames to tell puppy and tulip stories using “fewer” and “more”. Students solve Compare, Difference Unknown story problems with language that suggests the opposite operation. For example, problems that use a comparison statement with “more,” but require subtraction to solve. Students will work more with these problem types in grade 2.

When students make choices, adhere to constraints, and analyze real-world situations with mathematical ideas they model with mathematics (MP4).

• Each group of 2 needs at least 20 paper triangles.

• Each group needs their origami stories from the previous activity.

Think about a recent time from class when your students were confused. What did you do to support them in reasoning about their confusion together as a community of learners?