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✏️ ARITHMETIC
- Percent Formula: (Part / Whole) × 100
- Percent Change: [(New – Old) / Old] × 100
- Average (Mean): Sum of terms / Number of terms
- Median: Middle value when numbers are in order
- Mode: Value that appears most frequently
- Range: Largest value – Smallest value

🔢 ALGEBRA
- Quadratic Formula: x = [-b ± √(b² – 4ac)] / (2a)
- FOIL Method: (a + b)(c + d) = ac + ad + bc + bd
- Exponent Rules:
- am × an = am+n
- am ÷ an = am-n
- (am)n = amn
- a0 = 1 (for a ≠ 0)
- Inequality Rule: Reverse the inequality sign when multiplying/dividing by a negative number

📐 GEOMETRY
- Triangle Area: (1/2) × base × height
- Pythagorean Theorem: a² + b² = c²
- Sum of Interior Angles of a Polygon: (n – 2) × 180°
- Rectangle Area: length × width
- Rectangle Perimeter: 2 × (length + width)
- Circle Area: π × r²
- Circle Circumference: 2 × π × r
- Sector Area: (θ / 360) × π × r²

📊 DATA ANALYSIS & PROBABILITY
- Probability: Favorable outcomes / Total possible outcomes
- Combinations: nCr = n! / [r!(n – r)!]
- Permutations: nPr = n! / (n – r)!
- Standard Deviation: Square root of the average of the squared differences from the mean (conceptual understanding is key)
- Slope of a Line: (y2 – y1) / (x2 – x1)

💡 Tips for Using the Cheat Sheet Effectively
- Memorize core geometry and percent formulas
- Review exponent and algebra rules weekly
- Practice applying formulas using GRE-style questions
- Use scratch paper to track calculations and avoid careless errors