Subtraction of Positive and Negative Numbers: The Difference and Completion Approaches with Chips
August 2008, Volume 14, Issue 1, Page 21
An illustration of how the difference and completion (or missing addend) interpretations of subtraction may be used with chips of two colors to understand subtracting negative and positive numbers. Several visual representations are provided.
Addition and Subtraction
Skill and Fluency
Reasoning and Proof