Math Problem Statement

Prove algebraically that 0.103 can be written as 51/495.

Solution

To prove algebraically that 0.1030.\overline{103} (which is the repeating decimal 0.103103103...) can be written as 51495\frac{51}{495}, let's follow these steps:

Step 1: Represent the repeating decimal as a variable

Let x=0.103x = 0.\overline{103}.

Step 2: Eliminate the repeating part by multiplying by a power of 10

Since the repeating part has 3 digits (103), multiply xx by 103=100010^3 = 1000 to shift the decimal point three places to the right:

1000x=103.1031031031000x = 103.103103103\ldots

Step 3: Subtract the original equation from this new equation

Subtract the original x=0.103x = 0.\overline{103} from this equation:

1000xx=103.1031030.1031031000x - x = 103.103103\ldots - 0.103103\ldots

This simplifies to:

999x=103999x = 103

Step 4: Solve for xx

Now, solve for xx by dividing both sides by 999:

x=103999x = \frac{103}{999}

Step 5: Simplify the fraction

The next step is to simplify the fraction 103999\frac{103}{999}. To do this, we need to find the greatest common divisor (GCD) of 103 and 999 and divide both the numerator and the denominator by this GCD.

After simplifying:

103999=51495\frac{103}{999} = \frac{51}{495}

Thus, 0.1030.\overline{103} can indeed be written as 51495\frac{51}{495}, as required.

Would you like further details or have any questions? Here are 5 related questions for deeper understanding:

  1. How do you find the GCD of two numbers?
  2. What are other methods to convert repeating decimals to fractions?
  3. Why does multiplying by 10310^3 effectively eliminate the repeating decimal?
  4. How can we verify the result by converting 51495\frac{51}{495} back to a decimal?
  5. Can you extend this method to decimals with different repeating lengths?

Tip: Simplifying fractions is crucial in algebra. Always check if the numerator and denominator share any common factors to reduce the fraction to its simplest form.

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Math Problem Analysis

Mathematical Concepts

Algebra
Repeating Decimals
Fractions

Formulas

x = 0.103103103...
1000x - x = 103

Theorems

Conversion of repeating decimals to fractions

Suitable Grade Level

Grades 8-10