Subtracting Negative Integers by Adding the Opposite

Math with Mr. J

This math tutorial features Mr. J explaining the specific concept of subtracting a negative integer from another negative integer. The video breaks down the process by introducing the "Add the Opposite" strategy, which simplifies these potentially confusing problems into standard addition equations. Using a clear chalkboard format, the instructor demonstrates step-by-step how to rewrite subtraction problems as addition problems by changing the operation to addition and flipping the sign of the second number. The video explores two main themes: procedural fluency and conceptual understanding. First, it walks through two distinct examples ($-5 - (-9)$ and $-23 - (-10)$) to show the mechanical process of rewriting the equation. Second, it addresses the conceptual "why" behind the math by using a money analogy. Mr. J explains that negative numbers represent debt, and subtracting (taking away) debt is a positive action that increases one's financial value, helping students understand why the result is an increase in value. For educators, this video serves as an excellent direct instruction tool or review resource for middle school math units on integers. It effectively targets one of the most common stumbling blocks in pre-algebra—double negatives. Teachers can use this video to introduce the standard algorithm for integer subtraction, remediate struggling learners, or anchor a class discussion on why "two negatives make a positive" in subtraction contexts.