1. Course 1 2-5 Solving Subtraction Equations Course 1 Warm Up Warm Up Lesson Presentation Lesson Presentation Problem of the Day Problem of the Day

2. Warm Up Simplify. 1. x + 7 = 22 2. 18 + x = 105 3. 16 = x + 9 4. 23 = x + 4 x = 15 x = 87 x = 7 x = 19 2-5 Solving Subtraction Equations Course 1

3. Problem of the Day Bruce has 25 CD’s remaining after giving 14 to John, 17 to Mary, and 25 to Sue. How many CD’s did he begin with? 81 Solving Subtraction Equations 2-5 Solving Subtraction Equations Course 1

4. Learn to solve whole-number subtraction equations. 2-5 Solving Subtraction Equations Course 1

5. When John F. Kennedy became president of the United States, he was 43 years old, which was 8 years younger than Abraham Lincoln was when Lincoln became President. How old was Lincoln when he became president? 2-5 Solving Subtraction Equations Course 1

6. Abraham Lincoln’s age John F. Kennedy’s age – = 8 Let a represent Abraham Lincoln’s age. a – = 843 a – 8 = 43 + 8 a = 51 Abraham Lincoln was 51 years old when he became president. 2-5 Solving Subtraction Equations Course 1

7. y – 23 = 39 23 is subtracted from y. + 23 y = 62 Add 23 to both sides to undo the subtraction. Check y – 23 = 39 Substitute 62 for y in the equation. Solve y – 23 = 39. Check your answer. 62 is the solution. 39 = 39 ? Additional Example 1A: Solving Subtraction Equations 62 – 23 = 39 ? + 23 2-5 Solving Subtraction Equations Course 1

8. 78 = s – 15 15 is subtracted from s. + 15 93 = s Add 15 to both sides to undo the subtraction. Check 78 = s – 15 Substitute 93 for s in the equation. Solve 78 = s – 15. Check your answer. 93 is the solution. 78 = 78 ? Additional Example 1B: Solving Subtraction Equations 78 = 93 – 15 ? + 15 2-5 Solving Subtraction Equations Course 1

9. z – 3 = 12 3 is subtracted from z. + 3 z = 15 Add 3 to both sides to undo the subtraction. Check z – 3 = 12 Substitute 15 for z in the equation. Solve z – 3 = 12. Check your answer. 15 is the solution. 12 = 12 ? Additional Example 1C: Solving Subtraction Equations 15 – 3 = 12 ? + 3 2-5 Solving Subtraction Equations Course 1

10. a – 4 = 7 4 is subtracted from a. + 4 a = 11 Add 4 to both sides to undo the subtraction. Check a – 4 = 7 Substitute 11 for a in the equation. Solve a – 4 = 7. Check your answer. 11 is the solution. 7 = 7 ? 11 – 4 = 7 ? + 4 Try This: Example 1A 2-5 Solving Subtraction Equations Course 1

11. 57 = c – 13 13 is subtracted from c. + 13 70 = c Add 13 to both sides to undo the subtraction. Check 57 = c – 13 Substitute 70 for c in the equation. Solve 57 = c – 13. Check your answer. 70 is the solution. 57 = 57 ? 57 = 70 – 13 ? + 13 Try This: Example 1B 2-5 Solving Subtraction Equations Course 1

12. g – 62 = 14 62 is subtracted from g. + 62 g = 76 Add 62 to both sides to undo the subtraction. Check g – 62 = 14 Substitute 76 for g in the equation. Solve g – 62 = 14. Check your answer. 76 is the solution. 14 = 14 ? 76 – 62 = 14 ? + 62 Try This: Example 1C 2-5 Solving Subtraction Equations Course 1

13. 1. x – 9 = 21 2. 14 = x – 3 3. x – 7 = 11 4. 16 = x – 14 5. x – 9 = 11 Lesson Quiz 6. Susan is taller than James. The difference in their height is 4 inches. James is 62 inches tall. How tall is Susan? x = 30 x = 17 x = 18 x = 30 x = 20 66 inches 2-5 Solving Subtraction Equations Course 1