1. Find the solution of h – 18 = 54: 3, 36, 62, or 72. You can test each number by substituting h in the equation. COURSE 2 LESSON 2-2 3 – 18 54 – 15 = 54 False 36 – 18 54 18 = 54 False 62 – 18 54 44 = 54 False 72 – 18 54 54 = 54 True Since the equation is true when you substitute 72 for h, the solution is 72. 2-2 Using Number Sense to Solve Equations

2. Use mental math to solve each equation. a.s – 9 = 5 COURSE 2 LESSON 2-2 What you think What number minus 9 equals 5? Since 14 – 9 = 5, s = 14. b.4z = 28 c.g + 7 = 11d. = 5 c6c6 What you think What number times 4 equals 28? Since 4 7 = 28, z = 7. What you think What number plus 7 equals 11? Since 4 + 7 = 11, g = 4. What you think What number divided by 6 equals 5? Since 30 ÷ 6 = 5, c = 30. 2-2 Using Number Sense to Solve Equations

3. The weight of a packing crate is 14.65 lb. The crate and its contents together weigh 85.21 lb. Estimate the weight of the contents. COURSE 2 LESSON 2-2 14.65 + c = 85.21 14.65 15 85.21 85Choose compatible numbers. 15 + c = 85What number added to 15 is 85? c = 70Use mental math. The contents of the crate weigh about 70 lb. Words crate’s plus contents’ equals total weight weight weight Let c = the weight of the contents. Equation 14.65 + c = 85.21 2-2 Using Number Sense to Solve Equations

4. Solve each equation. Use mental math or estimation. 1.q – 15 = 252.6r = 423.17.25 + s = 21.4 4. = 85.m – 39.8 = –101.03 q = 40 t = 10 COURSE 2 LESSON 2-2 r = 7s 4 m –61 80 t 2-2 Using Number Sense to Solve Equations