Solution 1.2:3a

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The denominator in the expression has
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<center> [[Image:1_2_3a.gif]] </center>
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<math>10</math>
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as a common factor,
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<math>\frac{3}{2\centerdot 10}+\frac{7}{5\centerdot 10}-\frac{1}{10}</math>
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and it is therefore sufficient to multiply the top and bottom of each fraction by the other factors in the denominators in order to obtain a common denominator,
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<math>\frac{3\centerdot 5}{20\centerdot 5}+\frac{7\centerdot 2}{50\centerdot 2}-\frac{1\centerdot 5\centerdot 2}{10\centerdot 5\centerdot 2}=\frac{15}{100}+\frac{14}{100}-\frac{10}{100}</math>
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The lowest common denominator (LCD) is therefore
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<math>100</math>
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, and the expression is equal to
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<math>\frac{15}{100}+\frac{14}{100}-\frac{10}{100}=\frac{15+14-10}{100}=\frac{19}{100}</math>

Revision as of 12:58, 11 September 2008

The denominator in the expression has \displaystyle 10 as a common factor,


\displaystyle \frac{3}{2\centerdot 10}+\frac{7}{5\centerdot 10}-\frac{1}{10}


and it is therefore sufficient to multiply the top and bottom of each fraction by the other factors in the denominators in order to obtain a common denominator,


\displaystyle \frac{3\centerdot 5}{20\centerdot 5}+\frac{7\centerdot 2}{50\centerdot 2}-\frac{1\centerdot 5\centerdot 2}{10\centerdot 5\centerdot 2}=\frac{15}{100}+\frac{14}{100}-\frac{10}{100}


The lowest common denominator (LCD) is therefore \displaystyle 100 , and the expression is equal to


\displaystyle \frac{15}{100}+\frac{14}{100}-\frac{10}{100}=\frac{15+14-10}{100}=\frac{19}{100}

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