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Introduction to Number System in Aptitude

The Number System is a fundamental concept in aptitude tests, forming the basis for various mathematical calculations and problem-solving techniques. It deals with different types of numbers and their properties.

Types of Numbers:

1. Natural Numbers (N): Counting numbers starting from 1, 2, 3, …
2. Whole Numbers (W): Natural numbers including 0 (0, 1, 2, 3, …).
3. Integers (Z): Whole numbers and their negative counterparts (…, -3, -2, -1, 0, 1, 2, 3, …).
4. Rational Numbers (Q): Numbers that can be expressed as a fraction (p/q, where q ≠ 0).
5. Irrational Numbers: Numbers that cannot be expressed as fractions (e.g., √2, π).
6. Real Numbers (R): The set of all rational and irrational numbers.
7. Prime Numbers: Numbers greater than 1 that have only two factors (1 and itself).
8. Composite Numbers: Numbers with more than two factors.

Understanding the number system is essential for solving aptitude problems efficiently, as it helps in quick calculations and logical deductions.