Chapter 10: Problem 21
In Problems \(21-26\), write the given repeating decimal as a quotient of integers. $$ 0.222 \ldots $$
Short Answer
Expert verified
The repeating decimal \( 0.222\ldots \) is equal to \( \frac{2}{9} \).
Step by step solution
01
Understand the Problem
The task is to convert the repeating decimal 0.222... into a fraction. The decimal repeats the digit '2' indefinitely.
02
Set up an Equation
Let \( x = 0.222\ldots \). We want to express this repeating decimal in terms of \( x \) as a fraction.
03
Eliminate the Repeating Part
To eliminate the repeating part, multiply both sides of the equation by 10 to shift the decimal point. This gives: \( 10x = 2.222\ldots \).
04
Subtract Equations
Subtract the original equation (\( x = 0.222\ldots \)) from the new equation (\( 10x = 2.222\ldots \)) to get rid of the repeating decimal:\[10x - x = 2.222\ldots - 0.222\ldots\]\[\9x = 2\]
05
Solve for x
Solve the equation \( 9x = 2 \) to find \( x \): \[x = \frac{2}{9}\]
06
Verify the Result
Verify that \( \frac{2}{9} \) is correct by converting it back to a decimal. Performing long division confirms that \( \frac{2}{9} = 0.222\ldots \), matching the original repeating decimal.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Converting Decimals to Fractions
Converting repeating decimals to fractions helps us express numbers in a simpler fractional form. For instance, consider the decimal 0.222... It repeats the digit '2' indefinitely. To convert it to a fraction, we rely on algebraic methods. Observing the pattern of repetition is crucial. A repeating decimal can always be expressed as a fraction.
- Assign a variable: Let \( x = 0.222\ldots \).
- Setup equations: Create another equation with a strategically shifted decimal.
- Subtract as needed to isolate the non-repeating parts.
Mathematical Equations
Mathematical equations are vital for expressing relationships between numbers, especially when dealing with repeating decimals. In our problem, consider the equation \( x = 0.222\ldots \). Think of it as a tool we use to capture the repeating nature of the decimal.
Setting up multiple equations like \( 10x = 2.222\ldots \) allows us to effectively analyze and manipulate the problem. This step includes multiplying by a power of ten to align decimal points, making subtraction straightforward. The equations provide a framework:
Setting up multiple equations like \( 10x = 2.222\ldots \) allows us to effectively analyze and manipulate the problem. This step includes multiplying by a power of ten to align decimal points, making subtraction straightforward. The equations provide a framework:
- Original equation represents the repeating decimal.
- Secondary shifted equation aids in eliminating repetition.
- Subtraction of the two equations leaves a non-repeating integer.
Long Division
Long division is a powerful method to verify that our fraction accurately represents the original repeating decimal. After converting 0.222... to \( \frac{2}{9} \), we use long division to validate. This calculation reaffirms that dividing 2 by 9 indeed yields 0.222...
Using long division, you:
Using long division, you:
- Divide the numerator (2) by the denominator (9).
- Note the repeated pattern in the quotient.
- Match this pattern to the repeating decimal concerned.