Warm – up: List all the different was we multiply fractions in real-life situations. (Start with...
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Warm – up: List all the different was we multiply fractions in real-life situations. (Start with the situation in your word problem from Friday.)
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Transcript of Warm – up: List all the different was we multiply fractions in real-life situations. (Start with...
Warm – up:
List all the different was we multiply fractions in real-life situations. (Start with the situation in your word problem from Friday.)
Multiplying & Dividing Fractions
Objective: Students will multiply and divide fractions in real world
situations, and model their solutions.
Multiplying Fractions
• Mixed numbers need to be changed to improper fractions first
• Simplify by dividing the numerators and denominators by the GCF
• Multiply the numerators• Multiply the denominators• Simplify the answer if needed
Find the product.
5
11
3
22
Change the mixed numbers to improper fractions.
5
6
3
8
5
11
3
22
Cross simplify—divide out the GCF of 3 and 6divide by 3
2
1
5
6
3
8
5
11
3
22
Multiply the numerators/denominators.
2
1
5
16
5
6
3
8
5
11
3
22
Simplify the answer.
2
1
5
13
5
16
5
6
3
8
5
11
3
22
Dividing Fractions
Division can be done through repeated subtraction.
3
12
3
21
3
12
3
11
3
1
3
21 1
3
1
3
11
3
2
3
11
3
1
3
1
3
2 0
3
1
3
1
There are 6 one-thirds in 2, therefore , 6
3
12
Division can also be shown with models.
Draw 2 unit squares
3
12
Division can also be shown with models.
Then divide each rectangle into thirds.
There are 6 thirds in the model so
3
12
.63
12
How much pie will each person get if 3 people share ½ of a pie equally?
Take the ½ of a pie and divide it into 3 equal pieces so . Each person will get 1/6 of the pie. 6
13
2
1
To divide fractions, multiply by the reciprocal of the 2nd number.
3
4
4
3
3
4
3
2
4
3
3
2 = =
1
3
4
3
2
3
4
3
2= = 9
8
4
3
3
2
=
Divide.
7
12
3
24
Divide. First change the mixed numbers to improper fractions.
7
12
3
24 = 7
15
3
14
Then multiply by the reciprocal of the 2nd number.
7
12
3
24 = 7
15
3
14 = 15
7
3
14
Multiply the numerators and denominators.
7
12
3
24 = 7
15
3
14 = 15
7
3
14
45
98
Simplify the answer.
7
12
3
24 = 7
15
3
14 = 15
7
3
14
45
98
45
82
It’s time for you to practice!
Classwork/Homework
Multiplying and Dividing Fractions Worksheet.
