Every course, every lesson
The first unit of each course is open to everyone. A subscription opens the rest: every lesson, its practice and review, in every course, and every part of the Explorations.
Monthly
…a month
Cancel any time; access lasts to the end of the month paid for.
Yearly
…a year
One payment a year. Cancel any time; access lasts to the end of the year paid for.
- Cancel any time
- 30-day refund
- Tax shown before you pay
Payments are handled by Paddle, our reseller and merchant of record, which adds the sales tax or VAT for your country and sends the receipts. See the terms and the refund policy.
Subscription benefits
Not a video course or a stack of worksheets: every lesson is something to move, predict and check, then practise and review until it stays.
All 1055 lessons across 22 courses, from Geometry and Calculus to Relativity and Quantum Physics. Follow a course from its first unit to its last.
New numbers each time, feedback on the exact mistake you made, and hints in three steps when you are stuck. Answers count in any equal form.
Every topic you finish comes back just as it starts to fade, further apart each time you get it right, across all your courses at once.
Jump to any topic you are studying in class, see what it builds on, and open the lessons it leans on when something is shaky.
Each guided walkthrough from start to finish, not only its first part.
Lessons and courses added while you are subscribed are yours at no extra cost.
| Free | Subscription | |
|---|---|---|
| Lessons | The first unit of every course (138 lessons) | All 1055 lessons |
| Practice and review | For the first units | For every lesson |
| Course maps and search | Every course | Every course |
| Explorations | The first part of each | Every part |
| Progress on every device | With a free account | Included |
Cancel any time; nothing more is charged. If it isn't for you, ask for a full refund within 30 days of your first payment (refund policy).
Not sure yet? Try a free lesson; the first unit of every course is open.