42 lines
850 B
Markdown
42 lines
850 B
Markdown
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---
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tags:
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- Mathematics
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- Prealgebra
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- fractions
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- division
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---
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# Adding and subtracting fractions
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## Adding/ subracting fractions with common denominators
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For two fractions $\frac{a}{c}$ and $\frac{b}{c}$ with a common denominator, their sum is defined as:
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$$
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\frac{a}{c} + \frac{b}{c} = \frac{a + b}{c}
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$$
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For example:
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$$
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\frac{2}{8} + \frac{3}{8} = \frac{5}{8}
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$$
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The same applies to subtraction:
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$$
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\frac{a}{c} - \frac{b}{c} = \frac{a - b}{c}
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$$
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## Adding/ subracting fractions without common denominators
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* Find the lowest common denominator for the two fractions
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* Use this to create two equivalent fractions
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* Add/subtract
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* Reduce
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Demonstration: $\frac{4}{9} + \frac{1}{6}$ :
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The lowest common denominator is **the smallest number divisible by both of the denominators of the fractions without remainder**.
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