Math practice graded by a computer algebra system.
Students type the answer in any equivalent form. Locus checks it symbolically, shows a worked solution, and records the attempt in your gradebook.
300,000+ generated problems across arithmetic, algebra, geometry, precalculus, calculus, linear algebra, and statistics, plus physics simulations. Free to start.
Factor completely: $3x^2 - 27$
Your answer
Correct. Equivalent to the key $3(x-3)(x+3)$.
$-3(3-x)(x+3)$ is also accepted; $3(x^2-9)$ is not, because it is not fully factored.
Grading
Free-form answers, checked for equivalence.
There is no multiple choice to guess from. The grader parses what the student typed and compares it to the answer key with a computer algebra system, so $\frac{1}{2}$, $0.5$, and $\frac{2}{4}$ all grade the same, and $(x+3)(x-3)$ is a correct factoring of $x^2-9$ while $x^2-9$ itself is not.
- Every answer type
- Expressions, equations, inequalities, intervals, sets, ordered lists, matrices, multi-part answers, and word answers, each with its own input widget and its own grader.
- Unlimited variants
- Problems are templates. $x^2 - a^2$ with $a$ from 2 to 12 is eleven problems with eleven answer keys; each student draws their own numbers, and a retry is a fresh variant.
- Standards alignment
- Skills carry Common Core codes (HSA-SSE.A.2 for the problem above). Filter a problem set by standard; read the gradebook by standard.
Feedback is immediate: the verdict, partial credit on multi-part answers, and a worked solution on demand. Wrong answers go into a spaced-repetition review queue.
Classroom
Classes, assignments, and a gradebook.
Build an assignment from sections (topic, skills, difficulty, count), set a due date and an attempt policy, and assign it to a class or a group within it. Every attempt is scored on the server with partial credit.
| Student | Factoring | Quadratics | Unit test |
|---|---|---|---|
| Chen, Bao | 92% | 88% | 100% |
| Okafor, Dami | 76% | 81%* | - |
| Rivera, Ana | 100% | 95% | 90% |
| Sato, Ren | 64% | - | 72% |
- Rostering
- Students join with a code or an email invite, sign in with their school Google account, and sync from Google Classroom or Clever rosters.
- Gradebook
- Scores per assignment and per student, click-to-edit overrides, a by-standard mastery view, and CSV export for your SIS.
- Corrections
- Students redo missed problems as fresh variants for partial credit back.
- Analytics
- Per-class and per-student skill accuracy, misconception tags on wrong answers, and time on task.
Beyond the grader
Physics simulations, worksheets, and your own problems.
- Physics
- Interactive simulations (mechanics, electromagnetism, waves, circuits, quantum) with missions and a graded quiz. Assign a physics set the same way as a math set; students run the sim in the browser and answer from their measurements.
- Worksheets
- Print any problem set as a PDF: a fresh draw of every template, with or without an answer key, for a paper day or a sub.
- Authoring
- Write your own templated problems in a guided editor with a live preview, or describe the problem and let the AI authoring assistant draft the template, variants, and solution for you to check and publish.
How it works
From sign-in to the first assignment.
- 1
Sign in with your school Google account
No password to create. Switch the account to a teacher account on the next page.
- 2
Create a class
Share the join code or send email invites; students sign in with their school accounts.
- 3
Assign a problem set
Pick a preset from the gallery or build one from sections, set the due date and attempt policy.
- 4
Read the gradebook
Scores land as students work. Verify your teacher account to publish presets to the public gallery.
Privacy
Built for district review.
- Student accounts hold a name and a school email. No ages, no birthdates, no IP addresses stored.
- No analytics and no third-party code on this site; every asset is served from our own domain.
- COPPA school authorization through the district DPA; Locus acts as a school official under FERPA.
- Student accounts are excluded from public leaderboards and profiles; media embeds are off unless the district authorizes them.
Districts and schools
Site licensing and rostering for a whole school.
Site licensing, bulk teacher verification, Clever and Google Classroom rostering, and curriculum-aligned preset libraries. Contact us with your school's details.
Contact usStart with one class.
Sign in, create a class, and assign a preset. Free to start; the teacher plan adds capacity when you need it.
Start teaching