Demystifying Desmos: Best practices for the SAT and ACT

Both the digital ACT and the SAT include a built-in Desmos graphing calculator you can use on the entire Math section: no separate no-calculator section, and nothing to bring from home. Learning to use the Desmos SAT or ACT calculator effectively before test day can save you real time on Math section questions. Below are the strategies that matter most, plus where and how to practice.

What is Desmos, and where is it used?

The SAT, which has been a computer-based test since 2024, and the digital version of the ACT both feature the Desmos calculator, a testing aid that offers a wider range of functions than most handheld calculators. Both exams use the integrated graphing version of the calculator, which lets you map equations and values directly on a graphical interface, adding a visual component to your problem-solving.

Getting comfortable with Desmos, alongside a strong grasp of key SAT Math and ACT Math concepts, is what makes it a genuine advantage.

Pro tip: The same calculator is also used on the PSAT/NMSQT and PreACT, so practice for these preliminary exams carries over.

Desmos calculator mastery for the DSAT and ACT

On the paper SAT or ACT, using a calculator meant manually punching in keys for complex problems. On the DSAT and digital ACT, the embedded Desmos graphing calculator is available throughout the entire Math section of both tests, including both Math modules on the digital SAT.

Use it to:

• Graph systems of equations to find intersection points
• Solve quadratic or parabolic equations
• Find intercepts and vertices
• Visualize inequalities
• Activate sliders to graph numerical constraints
• Plot regression lines or scatterplots
• Evaluate permutations, combinations, and other factorial expressions using !
• Solve coordinate-geometry problems with functions like distance() or midpoint()
• Assign and test different variables
• Pro tip: When defining variables for graphs, assign the values to “x” and “y” so Desmos knows how to graph them

The graphical interface comes in handy even when you’re not answering a strictly graph-based question. The calculator is best used for complex math questions, such as abstract algebraic manipulation and complex geometry or trigonometry found in more challenging SAT and ACT questions. Use it sparingly for more straightforward questions, which can often be answered more quickly through practice and pattern recognition.

How can you practice with the Desmos calculator?

Practicing with the built-in Desmos calculator is essential for effective SAT and ACT preparation. You don’t want test day to be your first time using it: familiarity is exactly what turns it into a secret weapon.

• Access the official practice tool here: Desmos practice site
• Practice using the calculator on the College Board’s Bluebook and the ACT’s Gateway application

Build the calculator into your daily study sessions by solving practice problems with it and using it during timed practice exams, so you’re ready to work efficiently on test day.

Tips and tricks for using the embedded Desmos calculator

Tip 1: Use sliders

When a problem asks you to evaluate constants, use the Sliders option to see a range of outcomes for an equation quickly. When you add a letter other than x or y, Desmos offers to add a slider for that letter.

For example, enter y = ax - 7. After clicking the “a” button, a graph with a slider appears, and you can drag the slider through a range of values. You can also click the “a” variable in the equation and type an exact value to set it directly.

Tip 2: Easily solve absolute value problems

Absolute value problems are quick to solve in Desmos. Try a sample equation like |x − 5| = 10. Click the keyboard icon, select the absolute value symbol, and use the graph to solve the equation.

Tip 3: Easily get fractions from decimals

If you’re given a number in decimal form, convert it to a fraction by clicking the fraction button.

Tip 4: Easily find the mean and median of a list

Finding the mean and median of a set of numbers under time pressure can be tricky. Desmos simplifies it: enter your set of numbers, click the Functions button, and select the mean or median option to get the result instantly.

This can make some problems much faster to solve, so look out for opportunities to use it on the real test.

What other calculators are allowed on the SAT or ACT?

The Desmos calculator can be used on both Math modules of the digital SAT and on the entire ACT Math section. The launch of the digital SAT in 2024 introduced a more streamlined structure and new calculator policies. On the older paper SAT, handheld calculators were allowed for only one math section. Today, students can use the College Board’s online Desmos calculator throughout the Math section, making it faster to work through problems.

If you prefer to bring your own calculator, both tests allow it. Approved types include:

• Four-function calculators
• Graphing calculators
• Scientific calculators

Calculators with CAS (computer algebra system) features are not permitted on either test. Note also that on the ACT, calculators are permitted only on the Math section, not on the Science section. For the most up-to-date accepted calculator list, check the SAT or ACT’s official calculator policy. Just remember that the built-in Desmos calculator has all the features you need, and using it effectively can save time compared to manually entering numbers and taking your attention off the screen.

Practice makes perfect

Dedicate time to practicing with the Desmos SAT or ACT calculator in a realistic context so you’re confident on test day. Visit the official Desmos testing practice site to explore all of its features. The tips above are only a starting point, as there are many more functions to discover that can streamline your problem-solving. Some features take a little trial and error, but consistent practice will prepare you thoroughly for the SAT or ACT Math section.

Remember, the Desmos SAT and ACT calculators are a supportive tool meant to enhance your performance, not complicate it. Their effectiveness depends on your familiarity and skill. And while the calculator can simplify calculations, a solid grasp of core math concepts is still what drives your best results, so strengthen your math skills alongside your calculator proficiency.

Conclusion

When used properly, the Desmos calculator is a helpful resource that can significantly boost your SAT Math or ACT Math performance. Taking time to practice with the Desmos testing calculator and thoroughly exploring its features will help you save valuable time and prevent avoidable mistakes.

It’s important to remember that while the ACT or SAT calculator can simplify your calculations, a solid grasp of core math concepts remains crucial for achieving the best results. Consistently using Desmos in realistic testing practice will build up your comfort level and skills. Ultimately, Desmos is designed to enhance your problem-solving abilities, not replace your mathematical understanding, so be sure to strengthen your math skills alongside your calculator proficiency.