Digital SAT Math: what’s tested and the formulas to know

The four domains

Shares are approximate and vary by form. The headline: Algebra and Advanced Math together are about 70 percent of the section. If your time is limited, that is where it belongs.

Algebra: the biggest, most learnable chunk

Linear relationships dominate: solving equations, interpreting slope and intercept, and solving systems of two equations. Most of these reward fluency, not cleverness. The single most useful skill is reading a word problem and translating it into an equation quickly and correctly. Slow, careful translation beats fast, sloppy setup every time. Know the slope formula, slope = (y₂ − y₁) / (x₂ − x₁), and slope-intercept form, y = mx + b, cold.

Advanced Math: functions and quadratics

This is where the calculator earns its keep. Quadratics, exponential growth and decay, polynomial expressions, and function notation. You should be comfortable with the quadratic formula, x = (−b ± √(b² − 4ac)) / 2a, factoring, and reading a parabola’s vertex and roots off a graph. Because Desmos is built in, many of these become graph-it-and-read-it problems rather than algebra grinds, which is a genuine strategy, not a shortcut.

Problem-Solving and Data Analysis

Real-world math: percentages, ratios and proportions, unit conversion, rates, and reading statistics from tables and graphs (mean, median, range, probability, and interpreting a line of best fit). The recurring trap is units, a question gives you minutes and asks for hours, or grams and asks for kilograms. Strategy: underline the units in the question before you compute, and check that your answer’s units match what was asked.

Geometry and Trigonometry

The smallest domain, and much of it is on the reference sheet: areas, volumes, the Pythagorean theorem, and special right triangles. What is not on the sheet, and worth knowing, is basic trigonometry: the SOH CAH TOA ratios (sine = opposite/hypotenuse, cosine = adjacent/hypotenuse, tangent = opposite/adjacent), and that a full circle is 360 degrees or 2π radians. Circle theorems and angle relationships show up too, so review those rather than relying on the sheet.

What the reference sheet gives you

The Math section keeps a reference sheet on screen the entire time. It includes common area and volume formulas (rectangle, triangle, circle, rectangular solid, cylinder, sphere, cone), the number of degrees in a circle and radians, and the side ratios of the special right triangles (30-60-90 and 45-45-90). You do not need to memorize these, but you do need to know they are there and how to use them.

The catch: stopping to read the sheet costs time. Students who score well have internalized the handful of formulas they use most and reserve the sheet for the ones they rarely touch.

Formulas worth memorizing anyway

• Slope: slope = (y₂ − y₁) / (x₂ − x₁)
• Slope-intercept line: y = mx + b
• Quadratic formula: x = (−b ± √(b² − 4ac)) / 2a
• Percent change: (new − old) / old × 100
• Pythagorean theorem: a² + b² = c²
• Trig ratios: SOH CAH TOA
• Exponential model: y = a · bₓ (b > 1 is growth, 0 < b < 1 is decay)

None of these are exotic, and knowing them by heart shaves seconds off question after question. Over 44 questions, that is the difference between finishing comfortably and running out of time.

Using the built-in Desmos calculator well

Desmos is powerful, and leaning on it is smart, not lazy. Graph a system to find its intersection, graph a quadratic to read its roots and vertex, or plug in answer choices to see which works. The one discipline: still set the problem up correctly. A calculator makes a correct setup fast; it makes a wrong setup wrong faster. Practice with it before test day so its habits are automatic.

How to actually get better

Math improvement is unusually trackable: you either can solve a type of problem or you cannot, and practice with review closes the gap fast. Take a full-length test to find your weak domains, then drill that domain until it is automatic. BrightSAT’s question bank filters by domain, skill, and difficulty, so you can build a set of, say, medium quadratics and grind exactly that. For the wider plan, see how to study for the Digital SAT.

Common questions