GRE Quant Formulas You MUST Know: Flashcards for Quick Revision

Why Formulas Matter in GRE Quant

Many GRE Quant problems don't explicitly ask you to recite a formula. Instead, they present a scenario where applying the correct formula is the fastest, or often the only, path to the solution. Knowing the area of a circle, the properties of exponents, or how to calculate simple interest can save you precious minutes and ensure you arrive at the correct answer.

Without these foundational formulas, you'd spend valuable test time deriving them from scratch or attempting convoluted solution methods. Memorization, when combined with understanding, is a powerful ally for GRE success.

Essential GRE Quantitative Reasoning Formulas

Here are the must-know formulas across the main GRE Quant topics. As you go through them, imagine how each one would look on a flashcard.

Arithmetic Formulas

• Percent Change: ((New Value - Old Value) / Old Value) × 100%
• Simple Interest: I = P × R × T (Principal × Rate × Time)
• Compound Interest: A = P × (1 + R/n)^(nt)
• Average (Arithmetic Mean): Average = Sum of terms / Number of terms
• Sum of an Arithmetic Series: Sum = (n/2) × (first term + last term)
• Divisibility Rules: e.g., a number is divisible by 3 if the sum of its digits is divisible by 3.
• Exponent Rules:
• x^a × x^b = x^(a+b)
• x^a / x^b = x^(a-b)
• (x^a)^b = x^(ab)
• x^0 = 1
• x^(-a) = 1/x^a
• (xy)^a = x^a × y^a
• Square Roots: √(xy) = √x × √y and √(x/y) = √x / √y

Algebra Formulas

• Quadratic Formula: For ax² + bx + c = 0, x = (-b ± √(b² - 4ac)) / 2a
• Difference of Squares: a² - b² = (a - b)(a + b)
• Perfect Squares: (a + b)² = a² + 2ab + b² and (a - b)² = a² - 2ab + b²
• Distance = Rate × Time: D = RT
• Work Rate Formula: 1/T_total = 1/T_1 + 1/T_2 + ...
• Absolute Value:
• If |x| = a, then x = a or x = -a
• If |x| < a, then -a < x < a
• If |x| > a, then x < -a or x > a

Geometry Formulas

• Area of a Triangle: A = (1/2) × base × height
• Pythagorean Theorem: a² + b² = c² (c is the hypotenuse)
• Special Right Triangles:
• 45-45-90: sides in ratio x : x : x√2
• 30-60-90: sides in ratio x : x√3 : 2x
• Area of a Square: s²
• Area of a Rectangle: length × width
• Area of a Parallelogram: base × height
• Area of a Trapezoid: (1/2) × (base1 + base2) × height
• Circumference of a Circle: C = 2πr or C = πd
• Area of a Circle: A = πr²
• Volume of a Rectangular Prism: V = length × width × height
• Volume of a Cylinder: V = πr²h
• Distance Formula: d = √((x2 - x1)² + (y2 - y1)²)
• Midpoint Formula: ((x1 + x2)/2, (y1 + y2)/2)
• Slope Formula: m = (y2 - y1) / (x2 - x1)

Data Analysis Formulas

• Probability: P(Event) = Favorable outcomes / Total possible outcomes
• Independent Events: P(A and B) = P(A) × P(B)
• Mutually Exclusive Events: P(A or B) = P(A) + P(B)
• Permutations (Order Matters): nPr = n! / (n - r)!
• Combinations (Order Doesn't Matter): nCr = n! / (r! × (n - r)!)
• Factorial: n! = n × (n-1) × ... × 1 and 0! = 1
• Range: Highest Value - Lowest Value
• Standard Deviation: Measures the spread of data points around the mean. Direct calculation is rarely required; conceptual understanding is what the GRE tests.

Mastering Formulas with Flashcards

Simply reading through a list of formulas isn't enough. To truly internalize them and make them accessible under pressure, you need an active revision strategy. This is where flashcards shine.

The Power of Active Recall

Flashcards force you into active recall. Instead of passively re-reading notes, you're actively trying to retrieve information from memory. This process strengthens neural connections, making information easier to access under test conditions.

How to Create Effective Flashcards

1. Front: Write the concept, type of problem, or a specific question. For example: "Area of a circle" or "How to find the median of an even set?"
2. Back: Write the formula clearly, along with any conditions or helpful tips. For the Pythagorean theorem: a² + b² = c², only for right triangles, c is the hypotenuse.
3. Include examples: For complex formulas or those with common pitfalls, add a simple numerical example on the back.
4. Categorize: Group cards by topic (Arithmetic, Algebra, Geometry, Data Analysis) for focused study sessions. For a deeper look at conceptual understanding behind each formula, see master GRE Quant algebra and geometry concepts.

Implementing a Flashcard Revision Schedule

• Daily review: Even 10 to 15 minutes of flashcard practice makes a significant difference when done consistently.
• Spaced Repetition: Review cards you struggle with more frequently, and well-known cards less often. Apps like Anki automate this, or you can do it manually with "know well," "somewhat know," and "don't know" piles.
• Mix topics: Don't drill only geometry formulas for a week. Mixing arithmetic, algebra, and data analysis cards keeps your recall sharp across all areas.

Put Your Knowledge to the Test

Once your flashcard deck is built, put that knowledge into action immediately. The best way to solidify formula knowledge under pressure is extensive practice with timed problems. The GRE Quantitative Reasoning prep app provides a wide range of practice questions with detailed explanations, so you can see exactly how each formula is applied in varied question formats. Combine this with the final weeks prep checklist to make sure your formula review is timed right before your exam date.

Conclusion

Mastering the essential GRE Quantitative Reasoning formulas is a non-negotiable step on your path to a high score. By systematically organizing these formulas using flashcards and reviewing them through active recall and spaced repetition, you'll build a strong mathematical foundation. Combine this with ample practice, and you'll be well-equipped to tackle any quantitative challenge the GRE puts in front of you.