Transcript Slide 1

Do Now 12/1/11

Copy HW in your planner.
 Text

p. 120, #10-38 evens
In your journal, estimate what fraction of your
day you spend on the following: school,
eating, traveling (by car or bus), sleeping,
extra-curricular activities. Then determine
how much “spare time” you have each day.
Objective
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SWBAT add and subtract fractions.
Section 3-5 “Adding and Subtracting Fractions”
Adding Fractions with Common Denominators
To ADD fractions with common denominators, add
their numerators together. Simplify if necessary.
Add the numerators
a b ab
 
c c
c
2 3

7 7
2 3 5
 
7 7 7
Subtracting Fractions with Common
Denominators
To SUBTRACT fractions with common
denominators, subtract their numerators. Simplify if
necessary.
Subtract the numerators
a b a b
 
c c
c
5 1

6 6
4 2
 
6 3
Try It Out!!
Solve
5 2

8 8
5 2 7
 
8 8 8
5 2

12 12
5 2
3 1
 

12 12 12 4
“Opp-opp”
6  5
  
18  18 
Put the negative
sign with the
numerator.
6 5 1


18 18 18
3 2
 
5 5
3  2
   
5  5
3  2 5

 1

5  5  5
Fractions with Different Denominators
To ADD or SUBTRACT fractions with different
denominators follow these steps:
1. Rewrite the fractions using a common denominator.
2. Add or subtract the numerators.
2 1

5 7
What is the common denominator?
5: 5, 10, 15, 20, 25, 30, 35, 40
7: 7, 14, 21, 28, 35, 42
2 ?

5 35
2  7 14

5  7 35 Equivalent
1 ?

7 35
1 5 5

7  5 35
14 5 19


35 35 35
fractions
Try It Out!!
Solve
1 2

7 3
3 14


21 21
3 14 17


21 21 21
7 1

12 4
7 3
 
12 12
Don’t forget your
integer rules.
“Opp-Opp”
-7 + (-3) = -10
 7  3  10


12 12
12
 10
5

12
6
Try It Out!!
Solve
6  1
  
11  4 
24  11 
   
44  44 
24  11 
35
     
44  44 
44
4 2
 
5 20
16 2



20 20
16  2



20 20
18
9


20
10
Don’t forget your
integer rules.
“Opp-Opp”
-16 + (-2) = -18
1 3 1
 
3 7 9
1 3 1
 
3 7 9
24  11 
   
44  44 
24  11 
35
     
44  44 
44
1 3 1
 
3 7 9
16 2



20 20
16  2



20 20
18
9


20
10
Don’t forget your
integer rules.
“Opp-Opp”
-16 + (-2) = -18
NJASK7 Prep
Homework
 Text
p. 228, #10-28 evens, 38-44 evens