D18 — Geometric Measurement: Relating Area to Multiplication and Addition
Problem Strings for Fluency and Beyond · Geometric Measurement: Relating Area to Multiplication and Addition
For the next few strings, you will be showing some rectangular areas and asking students to determine the perimeter and area for them. As you progress through the string show one image at a time with the given dimensions and ask, "What is the perimeter for this array?" Solicit student strategies and an equation to match their strategy. Then for the same array, ask the students "What is the area for this array?" Solicit strategies and the equation to match their strategy. Display the arrays using Appendix N on pp. 174-176.
The problems within the string have been chosen for students to continue to use the multiplication facts they know to solve these problems. The first problem is a helper multiplication problem to support students in understanding the string. Notice that the "columns" for each of the problems remains 10. Students will likely begin to use this information for finding the perimeter of each shape by just adding "20" to the sum of the lengths of the other two sides. To find the area they will also likely realize they just multiply. If your students do not yet have a good understanding of area and perimeter, you should use graph paper instead of an open array but keep the conversation on perimeter focused on linear distance (not the number of columns).
- What is the perimeter for this array? What is the area? (Appendix N)
- What is the perimeter for this array? What is the area? (Appendix N)
- What is the perimeter for this array? What is the area? (Appendix N)
- What is the perimeter for this array? What is the area? (Appendix N)
- What is the perimeter for this array? What is the area? (Appendix N)
Appendix N – Images for String D18
