1. GOAL 1 SUBTRACTING REAL NUMBERS To subtract a real number, ____ its ________. 2.3 Subtraction of Real Numbers EXAMPLE 1EXAMPLE 2 addopposite Example: Rewrite by adding the opposite: Add:

2. Extra Example 1 Extra Example 2 Simplify the expression: 10 – 5 + 14 – (–18). a. –6 – 3b. c. –15 – (–6) EXAMPLE 3 See page 781 for review on adding fractions.

3. Extra Example 3 Find the terms of 3x – 5. EXAMPLE 4 First, rewrite the expression as addition: The terms are 3x and –5.

4. Extra Example 4 Evaluate the function y = –x – 7 for these values of x: –2, –1, 0, and 1. Organize your results in a table and describe the pattern. 1 0 OutputFunctionInput Pattern: Each time x increases by 1, y decreases by 1.

5. Checkpoint 1. Evaluate the expression: –5 – (–3) + 4 – 1. 2. Find the terms of –7 – (–2x ). 3. Evaluate the function y = 1 – x for these values of x: –2, –1, 0, and 1. Organize your results in a table and describe the pattern. 1 –7 and 2x x–2–101 y3210 As x increases by 1, y decreases by 1.

6. GOAL 2 USING SUBTRACTION IN REAL LIFE 2.3 Subtraction of Real Numbers EXAMPLE 5EXAMPLE 6 In reporting gains or losses, it is common practice to use a plus sign (+) to indicate a gain and a minus sign (–) to indicate a loss. Note their use in examples 5 and 6.

7. Extra Example 5 and 6 The daily closing prices of a utilities stock for one week are given below. a) Find the change in the closing price from day to day. b) Write the changes you found in order. c) Find the difference of the greatest number and the least number. 122.76 – 121.42 = +1.34 123.51 – 122.76 = +0.75 121.19 – 123.51 = –2.32 117.06 – 121.19 = –4.13 b. c.

8. Checkpoint 1. The daily closing prices of a software company’s stock for one week are given below. a) Find the change in the closing price from day to day b) Write the changes in order. c) Find the difference of the greatest number and the least number. a. –5.7 +1.5 –2.1 –3.9 –5.7, –3.9, –2.1, 1.5 7.2

9. QUESTIONS?