1. Course 1 2-4 Solving Addition Equations Course 1 Warm Up Warm Up Lesson Presentation Lesson Presentation Problem of the Day Problem of the Day

2. yes no yes Warm Up Determine whether each value is a solution. 1. 86 + x = 102 for x = 16 2. 18 + x = 26 for x = 4 3. x + 46 = 214 for x = 168 4. 9 + x = 35 for x = 26 Course 1 2-4 Solving Addition Equations

3. 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? Solving Subtraction Equations 53 m Course 1 2-4 Solving Addition Equations

4. Learn to solve whole-number addition equations. Course 1 2-4 Solving Addition Equations

5. The equation h + 14 = 82 can be represented as a balanced scale. h + 14 82 Course 1 2-4 Solving Addition Equations 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 + 14 82

6. 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 Course 1 2-4 Solving Addition Equations –14 h = 68 Subtraction is the inverse, or opposite, of addition. If an equation contains addition, solve it by subtracting from both sides to “undo” the addition.

7. Solve the equation. Check your answer. Additional Example 1A: Solving Addition Equations x + 87 = 152 Check x + 87 = 152 x + 87 = 152 87 is added to x. x = 65 Course 1 2-4 Solving Addition Equations – 87 Subtract 87 from both sides to undo the addition. 65 + 87 = 152 ? 152 = 152 ? Substitute 65 for x in the equation. 65 is the solution.

8. 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 Course 1 2-4 Solving Addition Equations –18 Subtract 18 from both sides to undo the addition. 72 = 18 + 54 ? 72 = 72 ? Substitute 54 for y in the equation. 54 is the solution.

9. Solve the equation. Check your answer. Try This: Example 1A u + 43 = 78 Check u + 43 = 78 u + 43 = 78 43 is added to u. u = 35 Course 1 2-4 Solving Addition Equations – 43 Subtract 43 from both sides to undo the addition. 35 + 43 = 78 ? 78 = 78 ? Substitute 35 for u in the equation. 35 is the solution.

10. Solve the equation. Check your answer. Try This: Example 1B 68 = 24 + g Check 68 = 24 + g 68 = 24 + g 24 is added to g. 44 = g Course 1 2-4 Solving Addition Equations –24 Subtract 24 from both sides to undo the addition. 68 = 24 + 44 ? 68 = 68 ? Substitute 44 for g in the equation. 44 is the solution.

11. 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. How far is it from Cooperstown to Springfield? Additional Example 2: Social Studies Application It is 83 miles from Cooperstown to Springfield. 95 = 12 + d Course 1 2-4 Solving Addition Equations 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.

12. 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. How far is it from Jacobsville to East Valley? Try This: Example 2 The distance between Jacobsville and East Valley is 18 miles. 35 = 17 + d Course 1 2-4 Solving Addition Equations 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.

13. Solve each equation. 1. x + 15 = 72 2. 81 = x + 24 3. x + 22 = 67 4. 93 = x + 14 Lesson Quiz x = 57 x = 45 x = 79 56 inches 5. Kaitlin is 2 inches taller than Reba. Reba is 54 inches tall. How tall is Kaitlin? Course 1 2-4 Solving Addition Equations