Every GRE Quant question reduces to a small set of identities. This cheat sheet is what we'd give a student in the final week before test day. For curriculum see our GRE complete guide; for vocabulary see Top 1000 GRE words.
Arithmetic and number properties
Percent change: (new − old) / old × 100. Average: sum / count. Weighted average: Σ(value × weight) / Σ(weights). Divisibility: 3 if digit-sum divisible by 3; 4 if last two digits divisible by 4; 6 if divisible by 2 and 3; 9 if digit-sum divisible by 9.
Algebra
Distance = rate × time. Combined work rate: 1/T = 1/A + 1/B. Quadratic formula: x = (−b ± √(b²−4ac)) / 2a. Exponent rules: a^m × a^n = a^(m+n); (a^m)^n = a^(mn).
Geometry
Special triangles: 30-60-90 sides 1 : √3 : 2; 45-45-90 sides 1 : 1 : √2. Circle: area πr², circumference 2πr. Area of trapezoid: ½(b₁ + b₂)h.
Statistics and probability
Standard deviation increases when values spread out, unaffected by adding the same constant to every value. P(A and B) for independent = P(A) × P(B). P(A or B) = P(A) + P(B) − P(A and B).
Frequently asked questions
Are these formulas provided on the GRE?
No. The on-screen calculator is provided but no formulas are given. You must memorise them.
How many formulas do I need to memorise?
Roughly 40 covers >90% of questions. Add another 10–15 less common identities (work-rate variations, geometric mean) for full coverage.
Should I print this cheat sheet?
Yes. Print, annotate with your own examples, and review daily for the final two weeks.