Lesson plan

Solve perimeter word problems by using addition and subtraction strategies

teaches Common Core State Standards CCSS.Math.Content.3.MD.D.8 http://corestandards.org/Math/Content/3/MD/D/8
teaches Common Core State Standards CCSS.Math.Content.3.NBT.A.2 http://corestandards.org/Math/Content/3/NBT/A/2
teaches Common Core State Standards CCSS.Math.Practice.MP4 http://corestandards.org/Math/Practice/MP4
teaches Common Core State Standards CCSS.Math.Practice.MP6 http://corestandards.org/Math/Practice/MP6
teaches Common Core State Standards CCSS.Math.Practice.MP8 http://corestandards.org/Math/Practice/MP8

You have saved this lesson plan!

Here's where you can access your saved items.

Content placeholder

or to view additional materials

You'll gain access to interventions, extensions, task implementation guides, and more for this lesson plan.

Big Ideas: Addition and subtraction are related in a part to whole relationship. We can find the perimeter of a shape by adding the lengths of the sides. This lesson builds on students' work with adding the sides to find the perimeter of a polygon. This task uses a rectilinear polygon with sides that are both known and unknown. Students apply addition and subtraction strategies to figure out the length of a missing side to determine the perimeter of the polygon. By understanding that perimeter is additive, students will use different strategies in addition to rounding as one method to check the solution. The mathematical concepts in this lesson build towards students' future work with rectangles with similar areas. Vocabulary: perimeter, rectilinear, distance, width, length, additive, rounding Special Materials: grid paper (optional) ruler (optional)