Top 10 GRE Math Formulas You Need to Memorize

When it comes to the GRE – Quantitative Reasoning section, it's not about memorizing every formula you've ever seen in school. Instead, it's about knowing the right GRE math formulas—the ones that show up again and again in questions on algebra, geometry, and data analysis.

The good news? The list is shorter than you think. By focusing on a core set of high-yield GRE math formulas and actually practicing with them, you can make huge gains in both speed and accuracy on test day. In this guide, we'll walk through the top 10 formulas you need to memorize for GRE Quant—and how to use them effectively.

Along the way, we'll also talk about how an AI-powered GRE Quant tutor can help you drill these formulas in a smarter, more personalized way so they actually stick.

Why Memorizing Core GRE Math Formulas Matters

GRE Quant questions aren't designed to test obscure math. They test whether you can recognize patterns, apply standard formulas, and think logically under time pressure. If you have to re-derive formulas during the test, you'll burn precious minutes—and likely make more mistakes.

Memorizing key GRE math formulas gives you three big advantages:

• Faster recognition of problem types.
• Cleaner, more organized work—less trial and error.
• More mental energy left for truly tricky reasoning steps.

Let's dive into the top 10 GRE formulas you should absolutely know before test day.

1. Slope of a Line: m = (y₂ − y₁) / (x₂ − x₁)

Slope tells you how steep a line is and how quickly one variable changes relative to another. GRE Quant questions may give you two points and ask you to find the slope or compare slopes of two lines.

• Formula: m = (y₂ − y₁) / (x₂ − x₁)
• Key idea: Positive slope = rising line, negative slope = falling line, zero slope = horizontal line.
• GRE tip: Slope shows up in coordinate geometry, rate-of-change graphs, and word problems about linear relationships.

2. Line Equation: y = mx + b

This is the classic slope-intercept form, where m is slope and b is the y-intercept. GRE questions often ask you to interpret or construct line equations from graphs, tables, or descriptions.

• Know how to find b by plugging in a point (x, y).
• Recognize that parallel lines share the same slope.
• Perpendicular lines have slopes that are negative reciprocals.

3. Distance Formula and Pythagorean Theorem

The GRE loves right triangles and distance on the coordinate plane. Fortunately, both rely on the same underlying formula:

• Pythagorean Theorem: a² + b² = c² for right triangles.
• Distance formula: d = √[(x₂ − x₁)² + (y₂ − y₁)²].

Memorize common Pythagorean triples like (3, 4, 5), (5, 12, 13), and (8, 15, 17) to save time and avoid unnecessary square roots on GRE Quantitative Reasoning questions.

4. Area and Perimeter of Rectangles and Triangles

Geometry questions on the GRE Quant section often use basic shapes, but they combine them with algebra, ratios, or data interpretation.

• Rectangle area: A = l × w
• Rectangle perimeter: P = 2l + 2w
• Triangle area: A = ½ × base × height

On GRE word problems, always ask yourself: "Do I really know which side is the base and which segment is the height?" The height must be perpendicular to the base.

5. Circle Formulas: Circumference and Area

Circles appear in GRE Quant questions involving geometry, ratios, and even data interpretation. You only need two core formulas:

• Circumference: C = 2πr or C = πd
• Area: A = πr²

Make sure you're comfortable switching between diameter and radius and interpreting circle-related info in graphs or charts on the GRE Quantitative Reasoning section.

6. Percent Change: Percent change = (New − Old) / Old × 100

Percent questions are everywhere on the GRE—word problems, tables, charts, and even Quantitative Comparison. This formula helps you find increases and decreases quickly.

• Always use the original value as the "Old" number.
• Watch for multi-step percent changes (e.g., +20% then −10%).
• Remember: a 20% increase followed by a 20% decrease does not bring you back to the original value.

7. Simple and Weighted Averages

The average (arithmetic mean) formula shows up in many disguises on GRE Quant questions.

• Average: Average = (sum of terms) / (number of terms)
• Weighted average: Multiply each value by its weight, add them up, then divide by the total weight.

On the GRE – Quantitative Reasoning section, look for clues about groups with different sizes—this often signals a weighted average problem rather than a simple mean.

8. Exponent Rules

Exponents show up in algebra, functions, and data analysis. Instead of memorizing complicated expressions, focus on a few core exponent rules:

• a^m × a^n = a^(m + n)
• a^m / a^n = a^(m − n) (if a ≠ 0)
• (a^m)^n = a^(mn)
• a^0 = 1 (a ≠ 0)

These rules are key for simplifying expressions and comparing quantities in GRE Quantitative Comparison questions.

9. Ratio and Proportion Basics

Ratios appear in mixture problems, geometry, and word problems about groups. You should be comfortable moving between fractions, ratios, and actual counts.

• If a ratio is a:b and the total is T, each part is a/(a + b) × T and b/(a + b) × T.
• Proportion setup: a/b = c/d → cross-multiply: ad = bc.

On the GRE, ratio questions often hide in phrases like "for every" or "in the ratio of"—translate those into numeric ratios early.

10. Simple Probability: Probability = (Favorable outcomes) / (Total outcomes)

You don't need advanced probability for GRE – Quantitative Reasoning, but you do need to keep the basic formula in mind and pay attention to whether selections are with or without replacement.

• For independent events, multiply probabilities: P(A and B) = P(A) × P(B).
• For "at least one" problems, sometimes it's easier to calculate the complement: P(at least one) = 1 − P(none).

How to Memorize GRE Math Formulas So You Don't Forget Them

Memorizing GRE math formulas is not just about reading them over and over. You'll remember them much better if you use them repeatedly in context.

Try this simple routine:

• Create a one-page GRE math formula sheet.
• Choose 2–3 formulas per day and do 5–10 practice questions using only those.
• At the end of each day, rewrite the formulas from memory, then check.
• Once a week, do a mixed set of GRE Quantitative Reasoning questions and circle which formulas you used.

Over time, your brain will automatically link question types with the relevant GRE math formulas—exactly what you want on test day.

Let an AI Tutor Drill These GRE Formulas With You

Doing this all manually can be tiring: choosing questions, tracking which formulas you're weak on, and making sure you're improving over time. That's where an AI tutor built for GRE – Quantitative Reasoning can make a huge difference.

SimpUTech's AI Tutor for GRE Quant doesn't just throw random problems at you. It:

• Identifies which GRE math formulas you're struggling with—like exponents, area, or percent change.
• Gives you targeted practice questions that force you to use those formulas until they feel natural.
• Provides step-by-step explanations so you see exactly where each formula comes into play.
• Adapts in real time as you improve, so you're always working on your biggest score gains.

Instead of guessing what to review next, you get a clear path: memorize, apply, refine—and watch your GRE Quant score move upward.