Mississippi Math 6.NS.9a

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.

Describe situations in which opposite quantities combine to make 0. For example, a hydrogen atom has 0 charge because its two constituents are oppositely charged.

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 describe two changes that cancel each other out, such as gaining 5 points and losing 5 points. They write the changes as opposite numbers and show that their sum is 0.
What Mastery Looks Like: A student can pair each positive quantity with an equal negative quantity and explain why the total is 0. They can tell the difference between no change and nothing happening.
Common Misconceptions: Students may think any positive and negative numbers cancel, even when the amounts differ. They may also think a net change of 0 means the starting amount was 0.
How to Assess It: Exit ticket: An elevator starts on floor 3, goes up 4 floors, then down 4 floors. Write the two signed changes and explain why their sum is 0.

Lesson moves

Ways to Teach It

Give students five blue counters and five red counters, with blue worth +1 and red worth -1; have them pair counters and record the total.
Ask: An elevator starts on floor 3, rises 4 floors, then drops 4 floors. What changed, and where did it end?
Hand out cards numbered -10 to 10; have students find opposite pairs and write an addition equation for each pair.
Show a bank account starting at $20; have students record a $12 deposit and $12 withdrawal, then find the ending balance.

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