Math Problem Statement

Which of the fractions would be written as a terminating decimal and which would be written as a repeating decimal? Classify fractions: 7/25, 7/11, 4/5, 5/6, 8/15.

Solution

To determine which fractions correspond to terminating decimals and which correspond to repeating decimals, we need to examine their denominators after reducing them to their lowest terms.

Key Rule:

A fraction will result in a terminating decimal if its denominator (after simplification) only contains the prime factors 2 and/or 5. If the denominator contains any prime factors other than 2 or 5, the decimal will be repeating.

Let's go through each fraction:

  1. 7/25: The denominator is 25, which is 525^2. Since 25 is made up of only the prime factor 5, this fraction has a terminating decimal.

  2. 7/11: The denominator is 11, which is a prime number other than 2 or 5. Hence, this fraction has a repeating decimal.

  3. 4/5: The denominator is 5, which is a prime factor. Therefore, this fraction has a terminating decimal.

  4. 5/6: The denominator is 6, which factors into 2×32 \times 3. Since 3 is a prime number other than 2 or 5, this fraction has a repeating decimal.

  5. 8/15: The denominator is 15, which factors into 3×53 \times 5. Since 3 is present, this fraction has a repeating decimal.

Classification:

  • Terminating Decimal: 7/25, 4/5
  • Repeating Decimal: 7/11, 5/6, 8/15

Let me know if you would like further clarification or additional details!

Here are 5 relative questions to expand this topic:

  1. Why do prime factors 2 and 5 result in terminating decimals?
  2. Can you simplify fractions to check if they will have a terminating decimal?
  3. What is the difference between a repeating decimal and a terminating decimal?
  4. How can you convert a repeating decimal into a fraction?
  5. Can all fractions be converted into either a terminating or repeating decimal?

Tip: Always check the prime factorization of a fraction's denominator to determine whether it will terminate or repeat!

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Math Problem Analysis

Mathematical Concepts

Fractions
Decimals
Prime Factorization

Formulas

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Theorems

A fraction has a terminating decimal if the prime factorization of its denominator contains only the numbers 2 and/or 5.

Suitable Grade Level

Grades 5-7