2. Chapter 2 Lesson 3 Subtracting Integers pgs. 70-74 What you will learn: Subtract Integers Evaluate expressions containing variables What you will learn: Subtract Integers Evaluate expressions containing variables

3. Remember the Additive Inverse! When you subtract 6 - 8, the result is the same as adding 6 + (-8). When you subtract -3 - 5, the result is the same as adding -3 + (-5) Additive Inverse 6 - 8 = -2 6 + (-8) = -2 Same result

4. Key Concept To Subtract an integer, add its additive inverse! a - b = a + (-b) 5 - 9 = 5 + (-9) which equals -4 -2 - 7 = -2 + (-7) which equals -9

5. Now you try! 8 - 13 -4 - 10 -13 - 9 Subtracting a positive integer: -5 -14 -22

6. Subtract a Negative Integer: Do the same way as you subtract a positive integer--just add the Opposite (additive inverse)! 7 - (-3) = 7 + 3 To subtract -3, add 3 = 10 Your turn! -2 - (-4) -16 - (-3) 20 - (-15) 2 -13 35

7. Evaluate Algebraic Expressions: Evaluate x - (-6) if x = 12 x - (-6) = 12 - (-6) Replace the x with 12 = 12 + 6 To subtract 6, add its additive inverse, 6 = 18 Add 12 and 6

8. Show what you know! Evaluate s - t if s = -9 and t = 3 Evaluate a - b + c if a = 15, b = 5, and c = -8 Evaluate each expression if x = 10, y = -4 and z = -15 x - (-10) y - x x + y - z 20 -14 21