Understand π + π as the number located a distance |π| from π, in the positive or negative direction depending on whether π 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 context.

The Number System

Apply and extend previous understanding of operations with fractions to add, subtract, multiply, and divide rational numbers except division by zero.

Add and subtract integers and other rational numbers; represent addition and subtraction on a horizontal or vertical number line diagram.