Lesson objective: Solve problems using addition and subtraction to compare measured or estimated lengths of objects.

This lesson provides an opportunity for students to apply their knowledge and understanding of finding length differences through adding or subtracting to a real-life situation. Students are asked to design a guinea pig habitat by combining different-sized cages.

Key Concept students will use:

- Addition and subtraction can be used to compare measured or estimated lengths of objects.

Skills students will use:

- add and subtract within 20 (Grade 1, Unit 1)
- relating addition and subtraction to length ( Grade 2, Unit 3)

Students engage in Mathematical Practice 1 ( Make sense of problems and persevere in solving them) as they find multiple solutions to a problem.** **

**Vocabulary:**