Quantitative Aptitude – Odd Man Out & Series
Develop logical pattern-recognition skills to identify incorrect numbers or predict the next number in a sequence.
1. Types of Series
- Arithmetic: Constant addition/subtraction.
- Geometric: Constant multiplication/division.
- Square/Cube series
- Alternating patterns
- Prime/Fibonacci-based
2. Common Patterns
- +n, −n alternation
- ×2, ÷2 switching
- Add square/cube numbers
3. Odd Man Out
- Look for all following a rule except one (e.g., prime/non-prime, square/not square)
4. Example
Series: 2, 4, 8, 16, 33, 64 → Pattern: ×2; 33 breaks the pattern → odd man out = 33.
5. Exam Strategy
- Check for basic arithmetic/geometric patterns first.
- Convert numbers to squares/cubes for insight.
6. Caution
- Don't assume complex patterns too early; test simplest logic first.
Summary: Pattern spotting, basic math, and logic are key to solving number series and identifying the odd number out.