Master your mistakes
Free AP and SAT practice built around the mistakes students actually make. When you miss a question, Mistake Master identifies the misconception behind it and gives you practice aimed at that specific idea. No account required.
About ten questions on one topic. No account, no email.
Joining a class?
Enter your class code
Your teacher gave you a six character code. Enter it here and your practice counts for your class on any device you use.
No account and no email. Joined already on another device?
Teaching a class?
Set up a class in minutes
Create a class, share one join code, and watch which misconceptions are clearing across the roster. Sign in with a magic link, with no password to manage.
Coded rosters: students join with a code, never their real name.
Pick a course
Choose a course to see its units and start practicing.
Drill in the Blaster
The same practice questions, played as an arcade shooter. Each unit has its own creature set, and wrong shots still count: each one is tied to a misconception, same as in the drills.
Explore interactivesRun it with a class
Set up a class with coded rosters (no student names) and watch which misconceptions are clearing on the dashboard. Students rejoin with their code and PIN, so their work reaches your dashboard from any device.
Teacher guide
How it works
Every wrong answer points to a misconception
Every wrong answer points to a misconception
Each wrong answer choice on this site is tied to a specific, named misconception, based on documented ways students misunderstand each topic. When you miss a question, you see which idea tripped you up and get practice aimed at that idea.
Mastery rule
Two in a row clears it
Two in a row clears it
Each misconception stays on your list until you answer two of its questions correctly back to back. Practicing on your own needs no sign-up; your progress saves in this browser. In a class, your roster code and PIN report your results to your teacher's dashboard from any device you practice on.
Your dashboard
Every misconception, in one place
Every misconception, in one place
The dashboard gathers every misconception you have run into and shows which ones you have cleared and which still need work, across every unit and course.