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RATIONAL NUMBERS

Rational Numbers

Definition Of Rational Numbers

A Rational Number is a real number written as a ratio of integers with a non-zero denominator.

More About Rational Numbers

Rational numbers are indicated by the symbol Q
Rational number is written in  form, where p and q are integers and q is a non-zero denominator.
All the repeating or terminating decimal numbers are rational numbers.
Rational numbers are the subset of real numbers.

Examples of Rational Numbers

3/5,10.3,0.6,12/5,3/4 - All these are examples of rational numbers as they terminate.

Video Examples: Definition of Rational Numbers

Solved Example on Rational Numbers

Ques: Identify a number that is a rational number but not an integer.

Choices:

A. 
B. 10.3
C. - 3.523...
D. - 

Correct Answer: B

Solution:

Step 1: - 3.523... is a non-terminating and a non-repeating decimal number, so it is not a rational number.
Step 2:  = - 5 is a rational number and also an integer.
Step 3:  cannot be expressed as a quotient of two integers, so it is not a rational number.
Step 4: 10.3 = 103 / 10 is a rational number, but not an integer.

Quick Summary

  • Rational numbers can be expressed as fractions.
  • Rational numbers can be expressed as terminating or repeating decimals.
  • Rational numbers are a subset of real numbers.
  • The set of rational numbers is denoted by Q.
\[ \frac{p}{q}, q \neq 0 \]

⚠️ Common Mistakes

  • Confusing rational numbers with irrational numbers (e.g., square root of 2).
  • Assuming all decimals are rational (non-repeating, non-terminating decimals are irrational).
  • Forgetting that the denominator cannot be zero.

📋 Standards Alignment

  • CCSS.MATH. content.7.NS.A.2
  • CCSS.MATH.content.8.NS.A.1

🍎 Teacher Insights

Use visual aids like number lines and pie charts to represent rational numbers. Emphasize the difference between rational and irrational numbers with examples. Relate rational numbers to real-world scenarios, such as sharing pizza or dividing quantities.

🎓 Prerequisites

  • Integers
  • Fractions
  • Decimals
  • Division

Check Your Knowledge

Q1: Which of the following is a rational number but not an integer?

Q2: Which of the following numbers is NOT a rational number?

Frequently Asked Questions

Q: Is zero a rational number?
A: Yes, because it can be written as 0/1.

Q: Are all fractions rational numbers?
A: Yes, as long as the numerator and denominator are integers.

Q: Are all integers rational numbers?
A: Yes, because any integer 'n' can be written as n/1.

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