Open Desmos when graphing, systems, or a messy calculation would eat the minute. Skip it for one-step arithmetic you can do in your head. Whether the tool is available at all is in Desmos on the ACT.
Leave it closed
Percent of a round number, a single plug-in, or “which is larger” among four tidy choices is faster by hand. Opening the keypad, typing, and reading a decimal back can cost more than the arithmetic. The same judgment for a handheld calculator is in when not to use your calculator.
Open it on purpose
Systems, a quadratic you do not want to factor, a regression, or a check of an answer you already found. Using it as a check, not as the first move, is in using Desmos to check. The built-in tools around it are in digital ACT tools.
The bottom line
If you can see the answer in a few seconds, do not type it. If the algebra is the slow part, graph it.
Start practicing
Start with a free diagnostic, then drill your weak spots with 15-question quizzes and track how you're doing across Reading, English, and Math. Compare plans whenever you're ready to go further.
This article offers general ACT prep guidance. The ACT can change from year to year, including its format, scoring, policies, test dates, and fees, so always confirm the latest details on the official ACT website at act.org before you make decisions. ACT® is a registered trademark of ACT, Inc. thirty-six is not affiliated with, endorsed by, or sponsored by ACT.