4-3 Solving Addition and Subtraction Equations 2.) y - 4 = 12 What is the value of y? ____ What did you do to find y? _____________________ 1.) x + 2 = 13 What is the value of x? _____ What did you do to find x? _______________________ Inverse operations - operations that undo each other; opposite operations You will need to use the inverse operation to solve equations.

Solving +/- Equations (Balanced Scale Approach) Balanced Scale x + 2 = 7 1.) Think of an equation as a scale that must stay balanced. 2.) How would we solve this equation? __________________ 3.) If you remove 2 from one side of the scale, what will you need to do to keep the scale balanced? : T wo ways to show this: Vertical method Horizontal Method

Tips: 1.) Use the opposite operation to solve 2.)You must do the same thing to both sides of the equation Solve each addition equation using the opposite operation. Be sure to show the required step and check your answer. 1.) x + 6 = 38 3.) y + 3 = 124.) x - 5 = 12 5.) 11 + d = -146.) 15 = m + (-9) 7.) 46 = 4 + x8.) a - 12 = -5 2.) g + 15 = 120

Word Problems Steps: 1.) Identify what the variable represents 2.) Write and solve the equation. 3.) Write your answer in a sentence 1.) Susan's math teacher assigned x homework problems on Monday. On Tuesday, she assigned 15 problems. Over the two days, a total of 24 homework problems were assigned. Write an equation and solve the equation to find the number of problems she assigned on Monday. 2.)You pay $1.70 for a box of oatmeal after using a coupon for $.80 off. Find the regular price of the oatmeal.

Demonstrate Understanding: Solve each equation. Show required step. 1.) r - 33 = 482.) y + 12 = 30 3.) 42 = x ) 24 = y ) m + (-4) = 17 6.) m 14 = ) q + 9 = ) -7 = y - 9

7.) You spend $12.75 at the movie theater You purchase a ticket and a container of popcorn for $3.25. How much does the movie ticket cost? Steps: 1.) Identify what the variable represents 2.) Write and solve the equation. 3.) Write your answer in a sentence