Terms of use

What you can do

• Use every tool without an account, payment or attribution requirement.
• Print the cheat sheet and the practice pages and hand them out in a classroom.
• Link to any page, including result URLs from the verifier and the chooser.
• Quote a formula freely — mathematical statements are not owned. The identities are also published as data at /data/identities.json; if you want to republish the wording or the dataset in bulk, contact us first and we will say yes or point you to a source with a clear licence.

What not to do

• Do not present the sampling check as a formal proof — the accuracy policy says what it is.
• Do not scrape the site and re-serve it as a "solver"; the value here is the checked data, not the traffic.

No warranty

The site is provided as-is, without warranty. Errors are possible: the build checks the mathematics it can check, and a wrong statement in the data would be a bug — see how to report it. Marks, safety decisions and published standards belong to the authority that issues them, not to this site.

Data version 2026.09.26-1.