Pricing
Lessons are free. Courses are how you get tested.
Every lesson, the solver and the visuals stay free. What is paid for is assessment: unit quizzes, final exams that a person reviews, and checks of your own working.
Course pass
$39
Every unit quiz, the final exam with one retake, and 20 checks of your own working, for one course.
One final exam
$15
A single sitting of one course's final, marked and reviewed. For someone who already knows the material and wants it tested.
Every course
$19/mo
All quizzes and finals in every course (two finals per course a month) and 100 working checks a month. Cancel from your account.
SubscribeWorking checks
$9
Ten checks: upload a photo of any working, or type it, and see where it went wrong.
Buy ten checks