1. Warm Up
Problem of the Day
Lesson Presentation
Lesson Quizzes

2. Warm Up 1. 5x = 20 2. 7n = 84 3. 18 = y – 4 4. 21 = n + 3 x = 4 n = 12
Solve.
1. 5x = 20
2. 7n = 84
3. 18 = y – 4
4. 21 = n + 3
x = 4
n = 12
y = 22
n = 18

3. Problem of the Day
If 11 is 4 less than 3 times a number, what is the number? 5

4. Learn to solve whole-number division equations.

5. Recall that multiplication and division are inverse operations
Recall that multiplication and division are inverse operations. If an equation contains division, solve it by multiplying on both sides to “undo” the division.

6. Additional Example 1A: Solving Division Equations
Solve the equation. Check your answer. x 7
= 5
x is divided by 7. x 7
= 5
7  x 7
= 7  5
Multiply both sides by 7 to undo the division.
x = 35
Check x 7
= 5 35 7
= 5 ?
Substitute 35 for x in the equation.
5 = 5 ? 
35 is the solution.

7. Additional Example 1B: Solving Division Equations
Solve the equation. Check your answer. p 6
13 =
p is divided by 6. p 6
13 =
6  p 6
6  13 =
Multiply both sides by 6 to undo the division.
78 = p
Check p 6
13 = ? 78 6
13 =
Substitute 78 for p in the equation.
13 = 13 ?
78 is the solution. 

8. Solve the equation. Check your answer. x 2 = 9
Check It Out: Example 1A
Solve the equation. Check your answer. x 2
= 9
x is divided by 2. x 2
= 9
2  x 2
= 2  9
Multiply both sides by 2 to undo the division.
x = 18
Check x 2
= 9 18 2
= 9 ?
Substitute 18 for x in the equation.
9 = 9 ? 
18 is the solution.

9. Solve the equation. Check your answer. p 4 72 =
Check It Out: Example 1B
Solve the equation. Check your answer. p 4
72 =
p is divided by 4. p 4
72 =
4  p 4
4  72 =
Multiply both sides by 4 to undo the division.
288 = p
Check p 4
72 = ?
288 4
72 =
Substitute 288 for p in the equation.
72 = 72 ?
288 is the solution. 

10. height of pine height of aspen = 3
Additional Example 2: Application
At Elk Meadows Park an aspen tree is one-third the height of a pine tree.
height of pine
height of aspen = 3
The aspen tree is 14 feet tall. How tall is the pine tree?
Let h represent the height of the pine tree.
Substitute 14 for height of aspen. h is divided by 3. h 3
14 =
3  h 3
3  14 =
Multiply both sides by 3 to undo the division.
42 = h
The pine tree is 42 feet tall.

11. Jamie’s father weighs 190 pounds.
Check It Out: Example 2
Jamie weighs one-half as much as her father.
father’s weight
Jamie’s weight = 2
Jamie weighs 95 pounds. How many pounds does her father weigh?
Let w represent her father’s weight.
Substitute 95 for Jamie’s weight. w is divided by 2. w 2
95 =
2  w 2
2  95 =
Multiply both sides by 2 to undo the division.
190 = w
Jamie’s father weighs 190 pounds.

12. Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems

13. Lesson Quiz
Solve each equation. Check your answers. x 10
= 7
2. 8 =
= 11
= 7
x = 70 x 4
x = 32 x 9
x = 99 x 15
x = 105
5. The area of Sherry’s flower garden is one- fourth the area of her vegetable garden. The area of the flower garden is 17 square feet. Let x represent the area of her vegetable garden. Find the area of her vegetable garden.
68 square feet

14. Lesson Quiz for Student Response Systemsx 5
1. Solve the equation = 15.
A. x = 3
B. x = 5
C. x = 20
D. x = 75

15. Lesson Quiz for Student Response Systemsx 7
2. Solve the equation 14 = .
A. x = 21
B. x = 28
C. x = 98
D. x = 121

16. Lesson Quiz for Student Response Systemsx 2
3. Solve the equation = 42.
A. x = 40
B. x = 44
C. x = 84
D. x = 104

17. Lesson Quiz for Student Response Systems3
4. Solve the equation = 30.
A. y = 99
B. y = 90
C. y = 33
D. y = 27

18. Lesson Quiz for Student Response Systems
5. The area of Linda’s rose garden is one-ninth the area of her lawn. The area of the rose garden is 15 square feet. Let x represent the area of her lawn. Identify the area of her lawn.
A. 9 square feet
B. 24 square feet
C. 135 square feet
D. 150 square feet