Page 863 - Algebra 1

Fraction Operations
Skills Bank Lesson 3
To add or subtract fractions with unlike denominators, first find a common denominator.
Adding and Subtracting Fractions
Example
1
a. Add_5and_3. 68
SOLUTION
Method 1: Multiply to find a common denominator.
Multiply by fractions equal to 1.
Add. Simplify.
Method 2: Find the lowest common denominator (LCD).
Multiples of 6: 6, 12, 18, 24, ... Multiples of 8: 8, 16, 24, ... The LCD is 24.
6 · 8 = 48
_5 _8 _3 _6
6(8)+ 8(6)
= 40 + 18 __
48
24 24
_5 _4 _3 _3 6(4)+ 8(3)
= 20 + 9 _ _
Multiply by fractions equal to 1.
Add.
=_ 48
24 24 _ _
48 58
29 5 = _ or 1_
= 29 or 1 5 24 24
b. Subtract_1 from_7. 28
SOLUTION
_7 _1 _4 8 - 2(4)
=_7 -_4 =_3 888
a. Multiply _2 · _5. b. Divide _5 ÷ _3. 36 45
Write equivalent fractions using a denominator of 8.
Multiplying and Dividing Fractions
Example
2
SOLUTION
Multiply the numerators and denominators. Then simplify if possible.
_2 ·_5 =_10 3 6 18
9 12 12
Skills Bank Practice
Add, subtract, multiply, or divide. Simplify if possible.
12 8
___ = 5 = 25 or 2 1
SOLUTION
Write the reciprocal of _3 and then 5
multiply. _5 ·_5 =_25
Multiplyby_5. 4 3 12 3
__ __ __ __ __ __ a. 7 + 3 b. 9 - 4 c. 5 · 3 d. 2 ÷ 9 e. 5 - 5 f. 7 + 8
848 Saxon Algebra 1
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