Practice for AP exams.
Every incorrect answer analyzed.
3,553 multiple-choice questions and 386 free-response prompts across eight exams. Each answer choice comes with the reason it is right or wrong, so a miss teaches you something. Try the one on this page.
AP Calculus AB · Unit 2 · Medium
How is the instantaneous rate of change of f(x) at x=a defined, in terms of a limit?
Pick one answer.
The exams
Section counts and timing as of 2026-27.
AP Biology
60 multiple choice, 6 free response. 3 h.
8 units, 542 questions, 48 free-response prompts
AP Calculus AB
42 multiple choice, 6 free response. 3 h 10 min.
8 units, 360 questions, 40 free-response prompts
AP Calculus BC
42 multiple choice, 6 free response. 3 h 10 min.
10 units, 529 questions, 55 free-response prompts
AP Computer Science A
42 multiple choice, 4 free response. 3 h.
10 units, 450 questions, 50 free-response prompts
AP Physics 1
40 multiple choice, 4 free response. 2 h 30 min.
8 units, 360 questions, 40 free-response prompts
AP Statistics
42 multiple choice, 4 free response. 3 h.
5 units, 502 questions, 47 free-response prompts
AP U.S. History
55 multiple choice, 3 short answer, 1 document-based question, 1 long essay. 3 h 15 min.
9 units, 405 questions, 53 free-response prompts
AP World History: Modern
55 multiple choice, 3 short answer, 1 document-based question, 1 long essay. 3 h 15 min.
9 units, 405 questions, 53 free-response prompts
How it works
- Answer a question, then read why each choice is right or wrong, not only the one you picked.
- Questions come back on a schedule, sooner when you miss them, so the app picks your weak spots for you.
- Work from a daily set of five, a timed full-length exam with an estimated score range, or a boss battle at the end of each unit.
- Free-response prompts come with a rubric and a sample answer. You grade your own work against them.
- A correct answer earns 10 to 25 XP by difficulty, plus up to 10 for your streak. Friends and classes get leaderboards, and you can opt out of them.
From students
“Wait this is actually tuff. I actually might use it later.”
Phu Vo
More subjects
None planned yet. No dates promised.
Every course we have built is open now. If we add another, you can hear about it.