1. EXAMPLE 1 Subtracting Integers –56 – (–9) = –56 + 9 = –47 –14 – 21 = –14 + (–21) = –35 Add the opposite of –9. Add. Add the opposite of 21. Add. a. –56 – (–9) b. –14 – 21

2. EXAMPLE 2 Evaluating a Variable Expression Evaluate 15 – a – b when a = 24 and b = – 36. 15 – a – b = 15 – 24 – (–36 ) = 15 + (–24) + 36 = –9 + 36 = 27 Add the opposite of 24 and of –36. Add –9 and 36. Substitute 24 for a and – 36 for b. Add 15 and –24.

3. EXAMPLE 3 Standardized Test Practice

4. EXAMPLE 3 Standardized Test Practice SOLUTION The height is the difference of the upper and lower elevations. Vertical height = –600 – (–1200) Write subtraction statement. = –600 + 1200 Add the opposite of –1200. = 600 Add ANSWER The height of the SOFAR channel is 600 meters. The correct answer is C.

5. GUIDED PRACTICE for Examples 1, 2, and 3 Evaluate the expression. Add the opposite of 41. Add. 1. 15 – 41 15 – 41 = 15 + (–41) = –26 2. –16 – 8 –16 – 8 = –16 + (–8) = –24 Add the opposite of 8. Add.

6. GUIDED PRACTICE for Examples 1, 2, and 3 a – b – (–6) = 8 – (–15 ) – 6 = 8 + 15 + 6 = 29 Add the opposite of – 15 and of –6. Substitute 8 for a and – 15 for b. Add. 3. a – b – (–6); a = 8, b = –15

7. GUIDED PRACTICE for Examples 1, 2, and 3 4. Distance What is the difference in elevation between 4 feet above sea level and 30 feet below sea level? The difference in elevation = 30 feet below sea level + 4 feet above sea level = 34 ft