Consider the statement: "The sum of any two rational numbers is a rational number." Is it true or false? If True, prove it directly. If False, provide a conterexample.

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**Title:** Understanding Rational Numbers

**Statement:** "The sum of any two rational numbers is a rational number." Is it true or false? If true, prove it directly. If false, provide a counterexample.

**Analysis:**
To determine the truth of this statement, recall the definition of a rational number. A rational number is any number that can be expressed in the form \( \frac{a}{b} \), where \( a \) and \( b \) are integers and \( b \neq 0 \).

**Proof:**
1. Let's consider two rational numbers \( \frac{a}{b} \) and \( \frac{c}{d} \).
2. To find their sum, use the formula for adding fractions: 

   \[
   \frac{a}{b} + \frac{c}{d} = \frac{ad + bc}{bd}
   \]

3. Here, \( ad + bc \) and \( bd \) are both integers (since they are results of integer operations: addition and multiplication).
4. Therefore, \( \frac{ad + bc}{bd} \) is a rational number because both the numerator and the denominator are integers and the denominator is not zero.

**Conclusion:**
The sum of any two rational numbers is indeed a rational number. The statement is true, as demonstrated by the above proof.
Transcribed Image Text:**Title:** Understanding Rational Numbers **Statement:** "The sum of any two rational numbers is a rational number." Is it true or false? If true, prove it directly. If false, provide a counterexample. **Analysis:** To determine the truth of this statement, recall the definition of a rational number. A rational number is any number that can be expressed in the form \( \frac{a}{b} \), where \( a \) and \( b \) are integers and \( b \neq 0 \). **Proof:** 1. Let's consider two rational numbers \( \frac{a}{b} \) and \( \frac{c}{d} \). 2. To find their sum, use the formula for adding fractions: \[ \frac{a}{b} + \frac{c}{d} = \frac{ad + bc}{bd} \] 3. Here, \( ad + bc \) and \( bd \) are both integers (since they are results of integer operations: addition and multiplication). 4. Therefore, \( \frac{ad + bc}{bd} \) is a rational number because both the numerator and the denominator are integers and the denominator is not zero. **Conclusion:** The sum of any two rational numbers is indeed a rational number. The statement is true, as demonstrated by the above proof.
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