48 lines
No EOL
1.6 KiB
Markdown
48 lines
No EOL
1.6 KiB
Markdown
---
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tags:
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- Mathematics
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- Prealgebra
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- fractions
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---
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# Mixed and improper fractions
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## Improper fractions
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* Proper fraction:
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* The numerator is smaller than the denominator
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* E.g. $\frac{2}{3}$, $-\frac{5}{10}$
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* Improper fraction
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* The numerator is greater than the denominator
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* E.g. $\frac{3}{2}$, $-\frac{5}{4}$
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## Mixed fractions
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A mixed fraction is part whole number, part fraction. For example: $5 \frac{3}{4}$.
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It means, in effect: $5 + \frac{3}{4}$
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## Converting mixed fractions into improper fractions
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Mixed fractions are hard to calculate with. We need some way to convert them to fractions. We can do this by converting them to improper fractions.
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With the example $4 \frac{7}{8}$, we know this means $4 + \frac{7}{8}$. We need to express the amount 4 in terms of eighths. It would be 4 lots of $\frac{8}{8}$ given that 4 is a whole number not a fractional amount. Thus the process would be:
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$$
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\frac{8}{8} + \frac{8}{8} + \frac{8}{8} + \frac{8}{8} + \frac{7}{8}
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$$
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But we know that when we [add fractions with a common denominator](./Add_Subtract_Fractions.md#adding-subracting-fractions-with-common-denominators), we only add the numerators, not the denominators. Thus the calculation would actually be:
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$$
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\frac{8 + 8 + 8 + 8 + 7}{8} = \frac{39}{8}
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$$
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Addition helps to explain the concepts underlying the procedure but it is more efficient to use multiplication.
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The procedure is as follows:
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1. Multiply the whole number part by the denominator
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2. Add the numerator
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3. Place the result over the denominator
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Thus:
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$$
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4 \frac{7}{8} = \frac{(4 \cdot 8) + 7 }{8}
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$$ |