1. Unit 8
Fractions and Ratios

2. Lesson 8.1
Comparing Fractions

3. Defining Fractions
Denominator – represents the number of equal sized pieces something is divided into (bottom number)
Numerator – indicates the number of those equal pieces being considered (top number)

4. Warm-Up (use reference page 399 to help)
Are the following fractions closer to 0, ½ , 1, 1 ½ , or 2
2/10
6/10
3/10
9/8
15/8
5/3
9/5
8/5

5. Renaming Fractions as Equivalent Fractions
Division Rule: Divide both the numerator and denominator by the same number yields an equivalent fraction.

6. Using your fraction sticks
Image from scimathmn.org
Using your fraction sticks

7. Comparing Fractions
Quick Common Denominator (QCD) – the product of the denominators or two or more fractions. (Quick way to get a common denominator, not the lowest common denominator)

8. Renaming Fractions as Equivalent Fractions
Equivalent means having the same solution set (They are EQUAL to each other)
Multiplication Rule: Multiply both the numerator and denominator by the same number yields an equivalent fraction.

9. Lesson 8.2
Adding Mixed Numbers

10. Improper Fractions
Improper Fraction: when numerator is greater than or equal to the denominator
examples:
5/3
39/31

11. Warm-Up: Rename as a whole, mixed, or improper fraction
3/3
2 ½
3/2
13/8
4 1/8
37/5
62/5
11 ¼

12. Adding fractions with the same denominator
When the denominators are the same, add the numerators and keep the common denominator.

13. What are mixed numbers? A whole number with a fraction Written:
Actually:

14. Adding Mixed Number with the same denominator
Everyday Math Way
1. Add the whole numbers
2. Add the fractions
3. Rename in simplest form

15. Let’s Practice Together
Problems will be reviewed on the white board

16. Adding mixed numbers with unlike denominators
1. find the common denominator for each fraction
2. use the adding mixed number technique
3. simplify
Let’s practice finding the common denominator

17. Let’s Practice Together
Problems will be reviewed on the white board

18. Subtracting Mixed Numbers
Lesson 8.3
Subtracting Mixed Numbers

19. Warm-Up (Find the QCD for the left and CD for the right)
answer: 6
5/6 and 7/9
answer: 54
4/5 and 7/10
answer: 50
7/10 and 19/20
answer 200
1/2 and 1/3
answer: 6
5/6 and 7/9
answer: 18
4/5 and 7/10
answer: 10
7/10 and 19/20
answer 20

20. Warm Up- (rename the fractions to have like denominators)
1/2 and 1/3
answer: 3/6 & 2/6
5/6 and 7/9
answer:15/18 & 14/18
4/5 and 7/10
answer: 8/10 & 7/10
7/10 and 19/20
answer:14/20 & 19/20

21. Subtracting Mixed Numbers with the same denominator
1. Rename (if necessary) the fraction on the top part of the equation larger than the bottom part. Example:
2. Subtract the fractions
3. Subtract the whole numbers
4. Answer in simplest form : Answer: 1 2/3

22. Let’s practice renaming fractions to make the fraction part larger
5 ¼
answer: 4 5/4
6 2/5
answer: 5 7/5

23. Let’s Practice Subtracting Mixed Numbers (Complete the following in your binder)
8 – 3 2/3
6 – ¼
4 3/5 – 1 4/5
6 5/12 – 3 11/12
answer: 4 1/3
answer: 5 ¾
answer: 2 4/5
answer: 2 ½

24. Complete Math Journal pg. 254
Answers:
1. 2 ½
2. 2 4/5
3. 5 ½
4. 4
5. 3
6. 23
7. 7
8. 7 2/3
9. 2 2/5
10. 3 ½
11. ¾ /3 /5

25. Subtracting fractions with unlike denominators
1. Find the common denominator or quick common denominator
2. Rename (if necessary) the fraction on the top part of the equation larger than the bottom part.
3. Subtract the fractions
4. Subtract the whole numbers
5.Answer in simplest form

26. Fractions of Fractions
LESSON 8.5 – 8.8
Fractions of Fractions

27. Using paper modeling (What is ½ of ½ ?)
Using a standard sheet of paper fold it in half vertically (the longer dimension)

28. ½ of ½ is ¼
Then fold it in half horizontally (the shorter dimension)

29. Lets try some more using paper modeling
What is 2/3 of 1/2
1st fold the paper in half (vertically) (shade 1 of the two)
Then in thirds (horizontally) (shade the 2 of the thirds)
Write and X on the parts shaded twice
Your answer should be 2/6 or 1/3

30. Continued
What is 3/4 of 2/3
1st fold your paper into thirds (vertically) (shade two of the thirds)
Then fold your paper into fourths (horizontally) (shade in three of the fourths)
Write an X in the parts shaded twice
Your answer should be 6/12 or ½
Practice with pg. 261 in your Math Journal

31. Multiplication Algorithm
¾ of ¼ =

32. Multiplication of Whole Numbers

33. Multiplication of Mixed Numbers

34. Multiplication of Mixed Numbers

35. Partial Products Method
1. Multiply the whole #’s
2. Multiply the 1st fraction and the 2nd whole number
3. Multiply the 1st whole # and the 2nd fraction
4. Multiply the 1st fraction and the 2nd fraction
5. Add the products

36. Finding a Percent of a Number
Lesson 8.9
Finding a Percent of a Number

37. Percent (%)
Definition – Per hundred, for each hundred, or out of a hundred. 1% = 1/100 = .01
Examples:
20% = 20/100 = .20
60% = 60/100 = .60
33% = 33/100 = .33

38. Let’s Practice What is 40% of 320? 1. Make 40% into a fraction.
40/100 or 4/10 or 2/5
2. Multiple
2/5 * 320/1
3. Simplify for your final answer

39. Discounts
Definition – The amount by which a price of an item is reduced in sale, usually given as a fraction or percent of the original price or as a percent off.
Example: An item that originally cost $10 at 10% off is now $9.00.
Remember – the discount is the amount to be subtracted from the original whole.

40. Let’s Practice
Hill’s Sporting Goods was selling all hockey equipment at a 25% discount. How much does each item cost after the discount?
Hockey Stick - $150
Helmet - $120
Philadelphia Flyers Jersey - $170
Goalie Leg Pads - $450

41. Division (Standard Algorithm)
How many _____ are in _____?
Ex: How many 2’s are in 10? ( ) 5
How many ½ are in 6? ( /2 ) 12
How many ¾ are in 5? (5 ¾)
6 2/3

42. Division (Common Denominators Method)
How many 4/5 are in 4? ( /5) 5
How many 5/6 are in 1/18? ( 1/ /6) 15