2-5 Addition Equations Warm Up Warm Up Lesson Presentation Lesson Presentation Problem of the Day Problem of the Day Lesson Quizzes Lesson Quizzes

2-5 Addition Equations Warm Up Determine whether each value is a solution x = 102 for x = x = 26 for x = 4 3. x + 46 = 214 for x = x = 35 for x = 26 yes no yes

2-5 Addition Equations Problem of the Day After Renee used 40 m of string for her kite and gave 5 m to her sister for her wagon, she had 8 m of string left. How much string did she have to start with? 53 m

2-5 Addition Equations Learn to solve whole-number addition equations.

2-5 Addition Equations inverse operations Vocabulary

2-5 Addition Equations The equation h + 14 = 82 can be represented as a balanced scale. h To find the value of h, you need h by itself on one side of the scale. h ? To get h by itself, first take away 14 from the left side of the scale. Now the scale is unbalanced. h 68 To rebalance the scale, take away 14 from the other side. h

2-5 Addition Equations Taking away 14 from both sides of the scale is the same as subtracting 14 from both sides of the equation. h + 14 = 82 –14 h = 68 Inverse operations undo each other. Addition and subtraction are inverse operations. If an equation contains addition, solve it by subtracting from both sides to “undo” the addition.

2-5 Addition Equations Solve the equation. Check your answer. Additional Example 1A: Solving Addition Equations x + 87 = 152 Check x + 87 = 152 x + 87 = is added to x. x = 65 – 87 Subtract 87 from both sides to undo the addition = 152 ? 152 = 152 ? Substitute 65 for x in the equation. 65 is the solution.

2-5 Addition Equations Solve the equation. Check your answer. Additional Example 1B: Solving Addition Equations 72 = 18 + y Check 72 = 18 + y 72 = 18 + y 18 is added to y. 54 = y –18 Subtract 18 from both sides to undo the addition. 72 = ? 72 = 72 ? Substitute 54 for y in the equation. 54 is the solution.

2-5 Addition Equations Solve the equation. Check your answer. Check It Out: Example 1A u + 43 = 78 Check u + 43 = 78 u + 43 = is added to u. u = 35 – 43 Subtract 43 from both sides to undo the addition = 78 ? 78 = 78 ? Substitute 35 for u in the equation. 35 is the solution.

2-5 Addition Equations Solve the equation. Check your answer. Check It Out: Example 1B 68 = 24 + g Check 68 = 24 + g 68 = 24 + g 24 is added to g. 44 = g –24 Subtract 24 from both sides to undo the addition. 68 = ? 68 = 68 ? Substitute 44 for g in the equation. 44 is the solution.

2-5 Addition Equations Johnstown, Cooperstown, and Springfield are located in that order in a straight line along a highway. It is 12 miles from Johnstown to Cooperstown and 95 miles from Johnstown to Springfield. Find the distance d between Cooperstown and Springfield. Additional Example 2: Social Studies Application It is 83 miles from Cooperstown to Springfield. 95 = 12 + d distance between Johnstown and Springfield distance between Johnstown and Cooperstown distance between Cooperstown and Springfield = + 95 = 12 + d –12 83 = d 12 is added to d. Subtract 12 from both sides to undo the addition.

2-5 Addition Equations Patterson, Jacobsville, and East Valley are located in that order in a straight line along a highway. It is 17 miles from Patterson to Jacobsville and 35 miles from Patterson to East Valley. Find the distance d between Jacobsville and East Valley. Check It Out: Example 2 It is 18 miles from Jacobsville to East Valley. 35 = 17 + d distance between Patterson and East Valley distance between Patterson and Jacobsville distance between Jacobsville and East Valley = + 35 = 17 + d –17 18 = d 17 is added to d. Subtract 17 from both sides to undo the addition.

2-5 Addition Equations Standard Lesson Quiz Lesson Quizzes Lesson Quiz for Student Response Systems

2-5 Addition Equations Solve each equation. 1. x + 15 = = x x + 22 = = x + 14 Lesson Quiz x = 57 x = 45 x = inches 5. Kaitlin is 2 inches taller than Reba. Reba is 54 inches tall. How tall is Kaitlin?

2-5 Addition Equations 1. Solve the solution of the x + 26 = 75. A. x = 39 B. x = 49 C. x = 59 D. x = 101 Lesson Quiz for Student Response Systems

2-5 Addition Equations 2. Solve the solution of the 71 = y A. y = 24 B. y = 28 C. y = 108 D. y = 118 Lesson Quiz for Student Response Systems

2-5 Addition Equations 3. Solve the solution of the z + 37 = 65. A. z = 102 B. z = 92 C. z = 38 D. z = 28 Lesson Quiz for Student Response Systems

2-5 Addition Equations 4. Solve the solution of the 76 = x A. x = 27 B. x = 37 C. x = 95 D. x = 115 Lesson Quiz for Student Response Systems

2-5 Addition Equations 5. Steven has 9 more music CDs than Carol. Steven has 25 music CDs. How many music CDs does Carol have? A. 7 music CDs B. 9 music CDs C. 16 music CDs D. 25 music CDs Lesson Quiz for Student Response Systems