converting a repeating decimal to a fraction
The following algorithm can be used to convert a repeating decimal to a fraction:
- 1.
Set the repeating decimal equal to .
- 2.
Multiply both sides of the equation by , where is the number of digits that appear under the bar.
- 3.
If applicable, rewrite the second equation so that its repeating part up with the repeating part in the original equation.
- 4.
Subtract the original equation from the most recently obtained equation. (The repeating part should cancel at this step.)
- 5.
If applicable, multiply both sides by a large enough power of so that the equation is of the form , where and are integers.
- 6.
Divide both sides of the equation by the coefficient of .
- 7.
Reduce the fraction to lowest terms.
Below, this algorithm is demonstrated for with the steps indicated on the far .
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An important application of this algorithm is that it supplies a proof for the fact that :