Apply and extend previous understandings of addition and subtraction to add and subtract rational numbers; 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.* - Understand
*p*+*q*as the number located a distance |*q*| from*p*, in the positive or negative direction depending on whether*q*is positive or negative. Show that a number and its opposite have a sum of 0 (are additive inverses). Interpret sums of rational numbers by describing real-world contexts. - Understand subtraction of rational numbers as adding the additive inverse,
*p*–*q*=*p*+ (–*q*). Show that the distance between two rational numbers on the number line is the absolute value of their difference, and apply this principle in real-world contexts. - Apply properties of operations as strategies to add and subtract rational numbers.

**7.NS The Number System **

**7.NS.A** *Apply and extend previous understandings of operations with fractions to add, subtract, multiply, and divide rational numbers.*