Mississippi Math 6.NS.9d

Math6th GradeThe Number System (NS) Apply and Extend Previous Understandings of Multiplication and Division to Divide Fractions by Fractions

The Standard

6.NS.9: Apply and extend previous understandings of addition and subtraction to add and subtract integers; represent addition and subtraction on a horizontal or vertical number line diagram.

Apply properties of operations as strategies to add and subtract integers.

2025 Mississippi College- and Career-Readiness Standards for Mathematics · Apply and Extend Previous Understandings of Numbers to the System of Rational Numbers

Teacher's field guide

What This Standard Means

What Students Need to Do: Students add and subtract positive and negative whole numbers. They turn subtraction into adding the opposite, then reorder or regroup additions to make the calculation easier.
What Mastery Looks Like: Given −9 + 4 + 9 − 6, a student pairs −9 with 9 and gets −2. They can explain why they may reorder additions but not subtraction.
Common Misconceptions: Students may calculate 5 − (−2) as 3 instead of 7. Some swap numbers in 5 − 8 as if subtraction could be reordered, or lose a negative sign while regrouping.
How to Assess It: Exit ticket: Calculate −7 + 12 − (−4) by rewriting the subtraction, then reordering the additions. Name the property that lets you reorder the terms.

Lesson moves

Ways to Teach It

Use red negative and blue positive counters to show 4 − (−3); add three zero pairs before removing three red counters.
Ask students to rewrite −8 + 3 + 8 as (−8 + 8) + 3 and explain which properties allow each step.
Play a card sort: match expressions such as 5 − (−2) and 5 + 2, then have partners explain each match.
Post a bank balance of −$12 with deposits of $8 and $12; have students reorder the transactions to find the new balance.

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