See what your students are actually getting wrong.
Every missed answer is tied to a specific misconception, so the console shows which ideas are causing problems across the class and which students need targeted practice.
Three ways in.
See class patterns, find the students who need targeted support, group them by the misconception they share, and print the practice.
Open the consoleEvery misconception Mistake Master tracks, organised by course and unit, with the coded distractors and the remediation behind each one.
Browse the librarySearch topics, learning objectives, essential knowledge, and misconception codes across every course framework, including the printed equations.
Search the frameworkWhat the console does with wrong answers.
Students practice, their wrong answers map to misconceptions, and the console turns that into a teaching plan. Three steps, and nothing to grade.
The console ranks every active misconception by how many students have it, so you walk in knowing what to teach first.
Cluster the students who share a trap into a reteach group, or mix strengths for balanced groups. Move anyone by hand.
Generate a worksheet with a teacher answer key for that group or misconception. Save as PDF or print it.
How the misconception tracking works.
Every wrong answer choice on this site is tied to one specific, named misconception, based on documented ways students misunderstand each topic. When a student misses a question, they see which idea tripped them up and get more practice aimed at that idea.
The clearing rule is simple: two correct in a row clears a misconception from the student's list. Items that recur across a course get re-checked in every later context, so a misconception that looked cleared early has to survive every later unit too. In physics, for instance, a sign error cleared in kinematics still has to hold up in forces, energy, and momentum.
Browser-based. No accounts. Solo progress saves to the device; class progress follows a roster code and PIN across devices.
What students actually bring in.
Every wrong answer choice on this site maps to a named misconception, and the ones below are the traps worth knowing before you teach the unit. Each note follows the same shape: the mistake, why it makes sense to the student, the correction, a sample item, and what each wrong answer reveals. Pick a course.
Common questions.
Can I track my class's progress?
Yes. Create a class in the teacher console and share a join code. As students practice, a live gradebook shows skill-check mastery and scores, and the class view ranks the misconceptions worth teaching first. No student emails or accounts.
Can I group students and assign targeted practice?
Yes. The console can cluster students who share a misconception into a reteach group, or mix strengths for balanced groups, then generate a printable practice worksheet with a teacher answer key for any group or misconception.
Is Mistake Master free?
Yes. Fully free, with no accounts required, no email walls, and no paid tier. It's built and maintained by a working classroom teacher.
Do students need to create an account?
No. Students can start using Mistake Master immediately by visiting the site; solo progress saves on that device. Students you add to a class get a roster code and PIN, which carries their progress across devices and reports their results to your dashboard.
Does it work on Chromebooks and iPads?
Yes. Mistake Master is browser-based, with no installs and no special permissions. It runs on Chromebooks, iPads, laptops, and phones.
How long is a typical session?
A unit diagnostic runs 5 to 10 minutes. Remediation drills typically run 1 to 3 minutes per active misconception. Students can use it in 10-minute warm-ups or longer review sessions; the platform picks up where they left off.
How does Mistake Master align with my course?
Course content is organized around the framework used for that course. For AP courses, items are mapped to the Course and Exam Description — topic, learning objective, and essential knowledge — and you can search all of it in Course Framework Search. AP Physics 1 is algebra-based throughout with no calculus notation, matching its specification; AP Physics C is calculus-based. SAT Math follows the College Board's digital SAT domains rather than a CED.
How is this different from Khan Academy or AP Classroom?
Khan Academy is a video and practice library. AP Classroom is the College Board's official progress-check system. Mistake Master sits between them: every wrong answer choice is tied to a specific named misconception, and the student keeps getting practice on that idea until they clear it twice in a row. Tying wrong answers to misconceptions is the key difference.
Can I assign specific units or topics?
Yes. Each topic and unit has a direct URL. Share the link to a specific diagnostic, lesson, or interactive with your class.
Why I'm building it.
Mistake Master started as a problem set I was hand-coding for my own classroom. The misconception coding came from teaching the same units year after year and noticing that students made the same wrong moves in the same places. Once that coding was there, adaptive remediation followed naturally.
It's a platform now, but it's still the same project: a teacher trying to make wrong answers do real pedagogical work, not just count against a score.
Create your class in under a minute.
Free, with no student accounts, on any Chromebook or iPad. Share a join code and results start showing up as students practice.
Get in touch.
I'd love to hear from you. Especially: errors you spot in the diagnostics or lessons, ways you're using it in your classroom, misconceptions I missed, and anything else worth saying.