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Published byFranklin Patrick Perkins Modified over 9 years ago
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+ Fractions: Addition & Subtraction Algebra Seminar 2012-2013
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Two Fractions can be combined easily when they have a common denominator.
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+ Def. Common Denominator- A number that all of the denominators divide into evenly.
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+ Common Denominator (similar to LCM) A number all original denominators divide into evenly 12 is a common denominator because 3 and 4 both divide 12 evenly.
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Least Common Denominator (same as LCM) To find the least common denominator * Write the times table list for each denominator * The smallest number that is in all rows is the least common denominator
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+ Least Common Denominator To find the least common denominator Write the times table list for each denominator The smallest number that is in all rows is the least common denominator
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+ The least common denominator is: 24!!!
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+ Practice - Find the common denominator for these fractions. 2 / 3 + 3 / 5 ¾ + 7 / 12 2 / 5 + 3 / 8 + 7 / 10
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What if the denominators do NOT match? If the denominators do not match, you must find the LCM to change them.
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+ Subtracting Fractions
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+ Subtraction – the process is the same but you will subtract the numerators instead of adding them. Squirt reminds you to: 1) Get a Common Denominator 2) Subtract
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+ Extra Practice
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+ Subtraction What is different about this problem? We have a mixed number! Lets change them to improper fractions!
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Subtraction Practice
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