5.3 multiplying fractions updated
15
• Before the bell rings... – Have your assignment out on your desk. – Have your covered textbook with you. 1. 13 2/9 + 133 1/3 = 2. Use words to write this number. 0.0616
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Transcript of 5.3 multiplying fractions updated
• Before the bell rings...– Have your assignment out on your desk.– Have your covered textbook with you.
1. 13 2/9 + 133 1/3 =
2. Use words to write this number. 0.0616
• Before the bell rings...– Have your assignment out on your desk.– Have your covered textbook with you.
1. 13 2/9 + 133 1/3 =
2. Use words to write this number. 0.0616
146 5/9
Six hundred sixteen ten thousandths
Essential Questions
1. What is the value of studying fractions?
2. What is the relationship between good number sense and working with fractions?
Fractions
Multiplying
Rule for x
1. Change the fractions to improper fractions
2. Divide out common factors
3. Multiply the numerator
4. Multiply the denominator
5. Simplify fraction into lowest terms
Try these examples
6
5
8
3
2
5
8
1
=
= =16
5
5
11
1
2 =
5
22
5
122 =
5
24
Try these examples
4
11
7
34
4
5
7
31= =
28
155=
28
155
EXAMPLE 1 Multiplying Fractions
a. – 25
– ( )23 = – 2 (– 2)
5 3Use rule for multiplying fractions.
=415
Evaluate numerator and denominator.
b. 310
– 56 = – 3 5
10 6Use rule for multiplying fractions.
= – 3 510 6
2
–1 1
2
Divide out common factors.
14
–= Multiply.
GUIDED PRACTICE for Example 1
Find the product. Simplify if possible.
1. 512
– 910 = – 5 9
12 10Use rule for multiplying fractions.
= – 5 912 10
2
–1 3
4
Divide out common factors.
38
–= Multiply.
SOLUTION
Write formula for area of a rectangle.
= 5 12
3 34
Substitute values.
=112
154 Write as improper fractions.
=11 152 4
Use rule for multiplying fractions.
EXAMPLE 2 Multiplying Mixed Numbers
PostcardsA postcard is inches long and 3 inches wide. Find the area of the postcard.
5 12
34
=1658
, or 20 58
Multiply.
Area length width=
EXAMPLE 2 Multiplying Mixed Numbers
The area of the postcard is square inches.
ANSWER
20 58
GUIDED PRACTICE for Example 2 and 3
Find the product. Simplify if possible.
5. 1 25 3 1
2 =75
72 Write as improper fractions.
=7 75 2
Use rule for multiplying fractions.
=4910
, or 4 910
Multiply.
GUIDED PRACTICE for Example 2 and 3
Find the product. Simplify if possible.
(–1 ) 6. 5 12
56 =
112
–116 Write as improper fractions.
=11 – 112 6
Use rule for multiplying fractions.
=–121
12, or –10 1
12Multiply.
GUIDED PRACTICE for Example 2 and 3
Find the product. Simplify if possible.
8. (– )2 13
34
– Write as improper fractions.
=– 7 – 3
3 4Use rule for multiplying fractions.
=74
, or 1 34
Multiply.
=–34
–73
( )
–1
1
Homework
• Page 245 #1-13, 19-20, 33-35
• Area– Rectangle = bh or lw– Triangle= ½ bh
