### Adding, Subtracting, Multiplying, and Dividing Fractions

```By: Mr. Menjivar
Observe,
Question,
Comment
09/02/11
Divide Fractions Reflection
09/02/11
Fractions
Warm-Up:
8L
8R
Change the Improper Fraction to Mixed
Number
#1)
111
9
#2)
16
7
Change the Mixed Number to Improper
Fraction
#3)
1
2
10
#4)
5
7
7
Observe,
Question,
Comment
09/02/11
Divide Fractions Reflection
Warm-Up:
09/02/11
Fractions
Standard
8L
8R


Number Sense 2.2: Add and subtract
fractions by using factoring to find common
denominators.
Number Sense 1.2: Add, subtract, multiply,
and divide rational numbers (fractions).
Observe,
Question,
Comment
09/02/11
Divide Fractions Reflection
Warm-Up:
09/02/11
Fractions
Standard
Objective
8L
8R


To multiply and divide fractions
Observe,
Question,
Comment
09/02/11
Divide Fractions Reflection
Warm-Up:
09/02/11
Fractions
Standard
Objective
Vocabulary
8L
8R


Are numbers expressed as the ratio of two
numbers


Tells the desired outcome


Tells you how many things are there in total


They’re fractions where the numerator is
bigger than the denominator.
Observe,
Question,
Comment
09/02/11
Divide Fractions Reflection
Warm-Up:
09/02/11
Fractions
Standard
Objective
Vocabulary
Notes/Examples
8L
8R
There are a few “special” fractions
How do you write 7 as a fraction?
7
1
How do you write 1 as a fraction?
3
101
3
101
How do you write 0 as a fraction?
0
0
5
100

(Use GCF if lost…)
4
9
2
9
1
10
7
10
4
9
2
9
2
7
14
7
Observe,
Question,
Comment
09/02/11
Divide Fractions Reflection
09/02/11
Fractions
Warm-Up:
Standard
Classwork #1
Objective
Vocabulary
Notes/Examples
8L
8R
Try these on your own =)
−5
9
4.) 4
3
5
5.) 5
6
4
6
−5
9
3
11
6
11
1.) 1
9
2.) −5
3.)
5
9
Observe,
Question,
Comment
09/02/11
Divide Fractions Reflection
09/02/11
Fractions
Warm-Up:
Standard
Classwork #1
Objective
Vocabulary
Notes/Examples
Back To The NOTES!!!!!!!!!!!!!
8L
8R

Step 1: Get a Common Denominator
1 3
−
6 4

Step 2: Make the denominators the
same

Step 3: Change numerators
accordingly

Step 4: Perform necessary operation
Parallel Example
Teacher (left) ; Student (right)
1
4
2
5
9
10
2
5
Parallel Example
Teacher (left) ; Student (right)
−5
6
3
8
3
4
−2
5
1
2
4
−
7
9
5
8
−
5
2
6

Suppose one day you rode a bicycle
1
3
2
1
1
4
for
hours and jogged for
hours.
How many hours did you exercise?

Observe,
Question,
Comment
09/02/11
Divide Fractions Reflection
09/02/11
Fractions
Warm-Up:
Standard
Classwork #1
Objective
Classwork #2
Vocabulary
Notes/Examples
8L
8R
Observe,
Question,
Comment
09/02/11
Divide Fractions Reflection
09/02/11
Fractions
Warm-Up:
Standard
Classwork #1
Objective
Classwork #2
Vocabulary
Homework
Notes/Examples
8L
8R


Pg. 313 [1-6 all and 13-16 all]
Pg. 314 [1-11 all]
Multiplying Fractions
All you do is multiply straight across!
1
4
1
4
1
16
4
5
2
5
8
25
Parallel Example
Teacher (left) ; Student (right)
5
9
2
9
3
7
2
7
Parallel Example
Teacher (left) ; Student (right)
3
−2
4
2
−5
3
3
−1
7
1
4
10
Dividing Fractions
Dividing is just like multiplying…
EXCEPT!!!
You are going to multiply the first fraction by
the reciprocal of the second fraction.
Dividing Fractions
What is a reciprocal?
It is the flipped version of a fraction.
The reciprocal of
4
5
5
4
4
1)
7
3
3)
10
2) 5
1
4)
2
Dividing Fractions
1
2
1
−
3
Parallel Example
Teacher (left) ; Student (right)
1
4
2
−
5
9
−
10
2
−
5
Parallel Example
Teacher (left) ; Student (right)
5
6
3
8
3
4
2
5

Break Time!
Observe,
Question,
Comment
09/01/11
Divide Fractions Reflection
09/01/11
Fractions
Warm-Up:
Standard
Classwork
Objective
Vocabulary
Notes/Examples
8L
8R
Observe,
Question,
Comment
09/01/11
Divide Fractions Reflection
09/01/11
Fractions
Warm-Up:
Standard
Classwork
Objective
Homework:
Vocabulary
Notes/Examples
8L
8R

Pg. 315 [1-8 all and 11-17 all and 21-23]
```