Instructional Activity# A Helpful Observation

Lesson 18. Unit 6. Grade 7 Open Up Resources

Open Up Resources10 min(s)

This Instructional Activity is a part of the Lesson 18, Unit 6, Grade 7. Students recall that subtracting a number (or expression) is the same as adding its additive inverse. This concept is applied to get students used to the idea that the subtraction sign has to stay with the term it is in front of. Making this concept explicit through a numeric example will help students see its usefulness and help them avoid common errors in working with expressions that involve subtraction.