How to Use Desmos on the SAT: The Complete Strategy Guide
Why Desmos is a Game Changer
Unlike the old SAT where the calculator was only allowed in one section and many students avoided it to save time, the Digital SAT gives you Desmos for the entire Math section — and knowing how to use it strategically can be worth 50–80 extra points.
What Desmos Can Do
- Graph any equation instantly
- Solve systems of equations visually
- Find x-intercepts (zeros) of parabolas
- Evaluate functions at specific x values
- Create tables of values
- Perform complex arithmetic without errors
Strategy 1: Solve Systems of Equations Visually
Instead of solving algebraically, graph both equations. The intersection point is your answer.
Example: For "y = 2x + 3 and y = −x + 9, find the solution", type both into Desmos and click the intersection point to read (2, 7).
Strategy 2: Find Zeros of Quadratics
When asked for x-values where a quadratic equals zero, type the quadratic into Desmos. The x-intercepts are your answers.
Example: x² − 5x + 6 → Desmos shows intercepts at x = 2 and x = 3.
Strategy 3: Graph to Understand Function Behavior
Many function questions ask about maximum/minimum values, domain/range, or what happens as x increases. Graph the function to see this visually.
Strategy 4: Verify Algebraic Work
After solving a problem algebraically, use Desmos to check your answer. Plug your answer back in and verify it satisfies the original equation.
Strategy 5: Evaluate Expressions Quickly
Desmos handles complex arithmetic without rounding errors. Use it for any calculation involving decimals, fractions, or large numbers.
How to Practice with Desmos
Access the same version of Desmos used on the SAT at desmos.com/scientific or inside the Bluebook practice tests. Practice using it from your very first study session — don't save it for test day.