Investigate the case of two negatives making a positive. Pupils fill in a quadrant system to generate the products of integers. They analyze the quadrants to find patterns and relationships to help complete the table values. The teacher leads the class in an algebraic proof to verify that the patterns were correct.

Concepts

integers, multiplication integers, negative integers, positive integers, additive inverse, zero product property, mathematical properties

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Additional Tags

math

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Instructional Ideas

• Emphasize the concept of giving away to represent a negative quantity
• Use a number line on the floor and have class members hop a given number of times a length to show multiplication

Classroom Considerations

• The class should understand the relationship between the signs of ordered pairs and the reflections across axes
• The lesson is installment 11 in a series of 25

Pros

• Uses two different approaches to arrive at the sign of the products
• Includes suggestions for visuals to place in the classroom

Cons

• The wording of the first lesson outcome makes it sound like absolute value can be negative
• The answer key for the problem set has some formatting issues that make it difficult to read

Common Core

7.NS.A.2.a MP7