1. Test 2 Review The test will consist of 3 sections.
Section 1 is vocabulary matching.
Section 2 is a Rate Per 100 problem.
Section 3 is a Unit Rate Problem.

2. Test 2 Review Vocabulary Matching
Rate one part in 100 or in this context
takes a quantity and calls that
quantity part of a whole. If
you divide that quantity into 100
pieces each piece would be
worth 1%.
Percent in this context is being used to
identify either a whole or part of a
whole.
Quantity is the amount of work or task
than can be accomplished
in a given time

3. Test 2 Review
John checks for bad hard drives on an assembly line. He saw 570 hard drives today. 45 of the hard drives were bad.
What percent of the hard drives were bad?
What percent of the hard drives were good?

4. Percent review you can skip to slide10 if you don’t need this 100%
This square is a 10 x 10 square. Each square is 1% of the total.
10 Squares are 10% of the
total.
If I had $ each square would be worth $1.00
$1. $1. $1. $1. $1. $1. $1. $1. $1. $1.

5. If I had $200.00 each square would be worth $2.00.
The $2.00 is found by dividing
the whole by 100.
20 Squares are 10% of the
Total and would be worth $20.00
If the whole or 100% is $200.00
If I had $ each square would be worth $1.00
$2. $2. $2. $2. $2. $2. $2. $2. $2. $2.

6. In terms of $100.00 each square is worth $3.42
It doesn’t matter what the whole is. If you divide the whole by 100 you
will always find 1%
= 3.42
3.42 = 1% or 1 square of the
whole or big square.
In terms of $ each square is worth $3.42
$3.42

7. Move the decimal
The nice thing about knowing that any number can be divided by
100 and you will find 1% is
that you don’t have to do long
division to solve it. Just take
the 100% and move the
decimal over two spaces to the left and you will
Have 1%.
$3.42

8. Move the decimal
100% = 1. 10% =.1 1% =.01 So if 542 = 100% 54.2 =10% 5.42=1%
$3.42

9. Move the decimal
100% = 1. 10% =.1 1% = = 100% 542 or you could say 54.2 X 10 = 542
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%

10. Move the decimal
100% = 1. 10% =.1 1% = = 100% If we divided each of the 54.2 boxes by 10 we would have 1% of the big box or 5.42% therefore 5.42 x 100 =542 and 5.42 = 54.2
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%

11. Move the decimal
100% = 1. 10% =.1 1% = = 100% Thinking about mathematical relationships if we divide 542 by 100 we get Using the inverse operation can be useful.
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%
54.2
10%

12. Solving the problem 570 hard drives = 100% So: 100% = 570 10% = 57
1% = 5.7
We want to know the percent that were bad so we need to know how many of the 1% squares 45 hard drives equal.
The small red square is both 1% and 5.7 hard drives. We need to
Find how many of these 1% squares total up to 45 hard drives.

13. Solving the problem
Your probably thinking that you could just add 5.7 until you get to 45 and that
would give you the percentage. You would be correct! However if we
remember our mathematical relationships unit we know that addition and
subtraction are inverses of one another so we could also just subtract 5.7
from 45 and count the number of times we did so to get the answer. This
would also work. A faster way would be to recognize that division is repeated
subtraction so we could just divide 5.7 into 45 and that would solve the
problem for us.

14. Solving the problem
So: Divide 5.7 into 45. To do this move the decimal to the right for both the 5.7 and the 45 hard drives. . Therefore you will have

15. Long Division
7. 89 % Therefore you will have As you can see we can continue to divide, but we can say we have approximately 7.89% of the hard drives that are bad. Or you could round up to approximately 8%.

16. Finishing up
Once we know that approximately 8% of the hard drives are bad we then can subtract 8% from the 100% total and we can say that approximately 92 % of the hard drives are good.
Complete sentence answers would be:
Approximately 8% of the hard drives are bad.
Approximately 925 of the hard drives are good.

17. Unit Rate Problems
If it took 3.5 hours to mow 6 lawns, then at that rate, how many lawns could be mowed in 20 hours?
How many lawns could be mowed in 20 minutes?
How could we use a ratio to solve this problem?
Try to build a model to solve this problem.
Use 5 methods to solve this problem.

18. Method 1 Traditional Approach
The ratio is 6 lawns: 3.5 hours
6 divided by 3.5 is approx lawns per hour
1.71 lawns per hour multiplied by 20 hours = 34.2 lawns.
Therefore approx lawns can be mowed in
20 hours.

19. Traditional approach continued
Now that you have solved what can be done in 20 hours lets solve the 20 minute question.
Based on what we have found already we know that we can do approx lawn per hour.
There are 3 20 minute intervals in an hour. Therefore we can divide 1.71 by 3 and we get .57 lawns per each twenty minute period.

20. The top model has been divided by 3 to show the increments in the
Method 2
Bar Model
6 lawns
3.5 hours
The top model has been divided by
3 to show the increments in the
lower model.
1.71 lawns
1 hour
1.71 lawns
1 hour
1.71 lawns
1 hour
.855 lawns
Per
Half
hour
34.2 lawns
In 20 hours

21. The top model has been divided by 3 to show the increments in the
Method 2
Bar Model
6 lawns
3.5 hours
1.71 lawns
1 hour
1.71 lawns
1 hour
1.71 lawns
1 hour
.855 lawns
Per
Half
hour
The top model has been divided by
3 to show the increments in the
lower model.
1.71 lawns
1 hour
The 1 hour block has been divided into three parts to show the
Twenty minute increments which are each .57 of a lawn in ½ hour. 20
Min
.57
lawns

22. Number Line Model Move of 2.5 hours Move of 3.5 hours LAWNS
HOURS
20 minutes

23. Table LAWNS HOURS .57 (approx) 20 minutes 1 .71 (approx) 1 6 3.5 12 718
10.5 24 14 30
17.5
(approx)
20 only moved 2.5 hours here

24. Ratio Table
Min
Hours /
Lawns
Approximately 34.2 lawns can be mowed in 20 hours.
Approximately .57 lawns can be mowed in 20 minutes.