Big Ideas:
The commutative property of addition applies when we add integers and rational numbers.
This lesson builds on students' previous work with positive and negative integers and understanding integers in context in sixth grade. The task asks students to represent the addition of positive and negative integers using the number line and to notice that the order of addition does not affect the result. Students are provided with the context of a disagreement between two students and are asked with whom they agree. It is building the understanding of the commutative property of addition through modeling on number lines.
Vocabulary: addend, sum, commutative property, equation, equivalent
Special Materials:
number lines
Lesson plan