Repeating decimals
Repeating decimals are decimal numbers in which one or more digits repeat infinitely. For example, the fraction equals , where the digit "3" continues indefinitely.
These decimals can be denoted using a bar over the repeating digit(s) (e.g., ). Repeating decimals arise from rational numbers, which are ratios of integers. Not every decimal is repeating; some are terminating (like ), while others are non-repeating and infinite (like or ).
In summary, repeating decimals provide a way to express certain fractions in decimal form, exhibiting periodicity in their digit sequences.
Part 1: Converting a fraction to a repeating decimal
When studying "Converting a fraction to a repeating decimal," focus on these key points:
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Understanding Fractions: Recognize that a fraction consists of a numerator (top number) and a denominator (bottom number).
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Long Division: Use long division to divide the numerator by the denominator. This is the main method for converting fractions to decimals.
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Identifying Repeats: If the long division process produces a remainder that has already occurred, the decimal will begin to repeat. Document the sequence of remainders to spot this.
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Repeating Decimal Notation: Use notation such as a bar (e.g., 0.3̅) to indicate the repeating part of the decimal.
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Terminating vs. Repeating: Understand the difference between fractions that yield terminating decimals (exact decimals that end) and those that yield repeating decimals.
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Prime Factorization: Know that a fraction will have a terminating decimal if, after simplification, its denominator contains only the prime factors 2 and/or 5.
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Converting Back: Be able to convert a repeating decimal back into a fraction if needed by setting up an equation and solving for the variable.
By mastering these points, you'll be well-equipped to convert fractions into repeating decimals.
Part 2: Converting repeating decimals to fractions (part 1 of 2)
Here are the key points for converting repeating decimals to fractions:
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Understanding Repeating Decimals: Recognize that a repeating decimal has a digit or group of digits that repeat indefinitely (e.g., 0.333... or 0.142857142857...).
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Identifying the Decimal: Clearly identify the repeating part of the decimal. For example, in 0.666..., "6" is the repeating digit.
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Setting Up an Equation: Let the repeating decimal be equal to a variable (e.g., let ).
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Multiplying to Eliminate the Decimal: Multiply the variable by a power of 10 that matches the number of repeating digits. For 0.666..., multiply by 10 to get .
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Subtracting the Original Equation: Subtract the original equation from this new equation to eliminate the repeating part. For example:
This simplifies to .
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Solving for the Variable: Solve for . Continuing from the previous step, divide both sides by 9:
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Simplifying the Fraction: Simplify the fraction to its lowest terms. In this case, simplifies to .
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Result Verification: Optionally, convert the fraction back to a decimal to confirm the result matches the original repeating decimal.
By following these steps, you can convert any repeating decimal into a fraction accurately.
Part 3: Converting repeating decimals to fractions (part 2 of 2)
Sure! Here are the key points to learn when studying "Converting repeating decimals to fractions (part 2 of 2)":
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Setup of the Equation: When converting a repeating decimal to a fraction, start by letting the repeating decimal equal a variable (e.g., ).
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Multiply to Shift Decimal: Multiply both sides of the equation by a power of 10 that matches the length of the repeating segment (e.g., for 0.666..., multiply by 10 to get ).
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Subtract the Original Equation: Set up a subtraction between the two equations (the original and the multiplied version). This helps eliminate the repeating part (e.g., ).
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Solve for : Simplify the resulting equation to solve for the variable. This will give you a numeric result (e.g., , thus ).
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Reduce the Fraction: Reduce the resulting fraction to its simplest form (e.g., ).
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Use of Mixed Numbers: If the repeating decimal is a mixed number (e.g., ), convert the whole number separately and combine it with the fraction derived from the decimal part.
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Special Cases: Be aware of any special cases, such as terminating decimals or non-repeating parts, and how they affect the conversion.
By following these steps, you can effectively convert any repeating decimal into a fraction.