Desmos® Tips for the SAT®: How to Use the Digital SAT® Calculator

The transition to the Digital SAT® (DSAT) introduces Desmos®, a built-in graphing calculator that replaces the need for a handheld device. Unlike traditional calculators, Desmos® offers dynamic graphing, equation-solving, and statistical tools, making it a powerful asset for test-takers. 

Horizon Education integrates Desmos® into our SAT® prep platform, allowing students to practice using the same tools they’ll encounter on test day. By incorporating Desmos®-based questions and strategies into instruction, teachers can ensure students are comfortable and confident using Desmos before test day.

Why Use Desmos® on the Digital SAT®?

Since Desmos is integrated into the Digital SAT® platform, students don’t need to bring a separate calculator. Key advantages include:

• Graphing capabilities for equations, functions, and inequalities.
• Quick calculations for exponents, logarithms, and statistical data.
• Dynamic sliders to adjust variables and visualize patterns.
• Time-saving tools that streamline problem-solving.

Should Students Bring Their Own Calculator?

While Desmos is provided, students can still bring an approved, handheld calculator:

• Graphing calculators (e.g., TI-84, Casio fx-9750GIII)
• Scientific calculators (e.g., TI-30XS Multiview)
• Basic four-function calculators (for simple calculations)

Key Desmos Strategies for the Digital SAT®

1. Solve Systems of Equations Instantly

Instead of using substitution or elimination, students can graph equations and find intersection points in seconds.

How to Do It:

1. Enter both equations into Desmos.
2. Identify the intersection point—this is the solution.
3. Click the point to see precise values.
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💡 Teacher Tip: Use practice problems where students solve systems both algebraically and graphically, so they know when Desmos is the best choice.

2. Graph Functions for Quick Answers

Rather than solving quadratics or polynomials manually, Desmos allows students to visualize key points instantly.

How to Do It:

• Input the function (e.g., y = x^2 - 5x + 7).
• Desmos highlights vertices, intercepts, and intersections automatically.
• Click points for precise values.

💡 Teacher Tip: Assign students practice questions where graphing the function first leads to a quicker answer.

3. Visualize Inequalities

Desmos makes solving inequality questions faster and more intuitive by shading solution regions.

How to Do It:

• Enter an inequality (e.g., y > 2x + 3).
• Desmos will shade the solution area automatically.
• For multiple inequalities, the overlapping shaded area represents the solution set.

💡 Teacher Tip: Have students compare algebraic vs. graphical solutions to reinforce conceptual understanding.

4. Use Sliders to Adjust Variables

The slider tool helps students dynamically test different values in equations.

How to Do It:

• Input an equation with a variable (e.g., y = ax + 3).
• When prompted, add a slider for 'a'.
• Adjust the slider to see how the graph changes.

💡 Teacher Tip: Use sliders to teach concepts like parallel lines, transformations, and no-solution conditions.

5. Speed Up Statistics Questions

Desmos simplifies data analysis with built-in statistical functions.

How to Do It:

1. Click “Functions” → “Statistics”.
2. Use commands like mean(), median(), stdev(), and range().

💡 Teacher Tip: Include real-world data sets for students to analyze using Desmos’ statistics tools.

6. Solve Absolute Value Equations Easily

Graphing absolute value equations can be much faster than solving them algebraically.

How to Do It:

• Enter an equation like |x - 4| = 9.
• The graph will show two intersection points—these are the solutions.

💡 Teacher Tip: Ask students to predict solutions algebraically, then confirm with Desmos.

7. Graph Circles in Seconds

Desmos simplifies circle equations, making it easy to find the center, radius, and key points.

How to Do It:

• Enter an equation in standard form: (x - h)^2 + (y - k)^2 = r^2.
• The graph will display the circle, center, and radius.

💡 Teacher Tip: Assign SAT-style problems involving tangents, secants, and circle equations.

8. Convert Decimals to Fractions Instantly

If a problem requires a fraction but the answer appears as a decimal, Desmos converts it automatically.

How to Do It:

• Enter the decimal value.
• Click the fraction button to convert it.

💡 Teacher Tip: This is especially helpful for percent-to-fraction conversions. Encourage students to use this tool to avoid unnecessary rounding errors.

How Teachers Can Help Students Master Desmos®

Teachers play a key role in helping students become comfortable with Desmos®  before the SAT®. With Horizon Education’s SAT® prep platform, educators can:

• Provide targeted Desmos practice with real SAT-style questions.
• Teach time-saving techniques for graphing, solving equations, and working with inequalities.
• Help students recognize when to use Desmos® vs. solving manually.
• Give students a test-day advantage by integrating Desmos into regular instruction.

The Desmos® calculator is a game-changer, but only if students know how to use it efficiently. Practicing beforehand ensures confidence and speed on test day. By mastering Desmos® shortcuts and techniques, students can maximize efficiency and accuracy, giving them a clear advantage on the Digital SAT®.

Let’s set students up for success—contact Horizon today to see how we can help your school.