Keep-Change-Change: Operating on Integers and Rational Numbers

Shared by Katie DeSanto★ Featured Teacher · rated 90+ in our quality review

6th GradeBuilding thumbing classrooms style50 min

Learning Objective

Students will add, subtract, multiply, and divide integers and rational numbers by applying the additive inverse strategy (keep-change-change) and number line reasoning.

Lesson Overview

Students begin with integer addition on a number line, then use the keep-change-change (KCC) strategy to rewrite subtraction as addition, before extending to multiplication and division of integers and rational numbers. Every task is anchored to a number line visual.

Materials

Whiteboard or large paper on a vertical surface
Dry-erase markers (or pencil and paper)
Pencil

Scaffolded Task Progression

1Task 1

Use the number line below to find each sum. Draw arrows showing your moves.
a)

3 + 5

- 2 + (- 4)

6 + (- 9)

[ Interactive graph / diagram, available in the full lesson ]

2Task 2

Rewrite each subtraction problem using Keep-Change-Change, then solve. Show the number line for part (c). KCC rule:

a - b = a + (- b)

7 - 10

- 3 - 5

- 1 - (- 6)

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