Instructional Activity# Toward a More General Slope Formula

Lesson 10. Unit 3. Grade 8 Open Up Resources

Open Up Resources15 min(s)

This Instructional Activity is a part of the Lesson 10, Unit 3, Grade 8. The purpose of this activity is to compute the slopes of different lines to get familiar with the formula "subtract y-coordinates, subtract x-coordinates, then divide." Students first compute slopes for some lines with positive slopes, and then special attention is drawn to the fact that a line has a negative slope. Students attend to what makes the same computations have a negative result instead of a positive result.