Adding Integers To add two integers with the same sign, find the sum of their absolute values. Use the sign of the two integers. To add two integers with different signs, subtract. Use the sign of the integer that is farthest from zero.

The integers are the set of whole numbers and their opposites The integers are the set of whole numbers and their opposites. Including zero. The whole numbers are the counting numbers and zero: 0, 1, 2, 3, . . . . Remember!

The opposite of a number is the same distance from 0 on a number line as the original number. Zero is its own opposite. –4 and 4 are opposites –4 4 • • –5–4–3–2–1 0 1 2 3 4 5 Negative integers Positive integers 0 is neither positive nor negative

A number’s absolute value is its distance from 0 on a number line. They are always positive or zero. The symbol is read as “the absolute value of.” For example -3 is the absolute value of -3. Reading Math

Example 1: Modeling Integer Addition Adding Integers Example 1: Modeling Integer Addition Use a number line to find each sum. –7 + (–4) +(–4) –7 2 –14 –12 –10 –8 –6 –4 –2 0 Start at 0. Move left 7 spaces. Then move left 4 more spaces. –7 + (–4) = –11

Insert Lesson Title Here Adding Integers Insert Lesson Title Here Example 2 Use a number line to find each sum. –4 + (–5) +(–5) –4 2 –14 –12 –10 –8 –6 –4 –2 0 Start at 0. Move left 4 spaces. Then move left 5 more spaces. –4 + (–5) = –9

Insert Lesson Title Here Adding Integers Insert Lesson Title Here Example 3 Use a number line to find each sum. –7 + 12 12 –7 2 4 6 8 –12 –10 –8 –6 –4 –2 0 Start at 0. Move left 7 spaces. Then move right 12 spaces. –7 + 12 = 5

Insert Lesson Title Here Adding Integers Insert Lesson Title Here Use a number line to find the sum. 1. –7 + (–6) Find each sum. 2. –15 + 24 + (–9) 3. –24 + 7 + (–3) 4. Evaluate x + y for x = –2 and y = –15. –13 2 –14 –12 –10 –8 –6 –4 –2 0 –20 –17