QED
Probability & Counting

Probability practice, graded like a real exam

Events, conditional probability, random variables. Probability rewards precision and repetition more than almost anything else on a probability & counting course — it is exactly the kind of topic where working through twenty varied problems beats re-reading the chapter a third time. QED gives you an endless supply of exam-grade probability questions and marks every answer the way an examiner would, so each attempt actually teaches you something.

First questions free · no card · no personal data stored

What you'll practise in Probability

  • Sample spaces & events
  • Conditional probability & independence
  • Bayes' theorem
  • Random variables & expected value
  • Variance & standard deviation
  • Binomial & uniform distributions

What a Probability question looks like

In a QED session, an exam-level probability question might ask you to compute a conditional probability, apply Bayes' theorem, or find the expected value and variance of a discrete random variable.

Every question carries a hidden marking rubric. You answer in real notation, and QED marks each criterion separately — awarding partial credit and showing a full worked solution, so you learn from the marks you dropped.

Why students use QED for Probability

Not another chatbot that blesses whatever you type. QED is built for deliberate practice — the way maths actually sticks.

Practice that never runs out

A textbook gives you a handful of probability exercises with the same worked answers everyone has seen. QED generates unlimited fresh probability questions at warm-up, exam and challenge level, so you can drill a weak spot until it is automatic — not until you run out of problems.

Marked like an examiner, not a checkbox

Most tools just say “correct” or “wrong”. QED marks your probability answer against a point-by-point rubric, awards partial credit, shows exactly where the reasoning slipped, and gives a full model solution. A right answer with the wrong argument still loses the argument marks — just like a real exam.

A library you can come back to

Every probability question you generate is saved, organised and re-takeable as a timed exam. Your mastery is tracked per topic, so you always know whether Probability is exam-ready or still needs work — and you can export any question or exam report to PDF.

Write maths the way you actually write it

Answer in real notation with a one-tap symbol palette and a visual equation editor, drop in truth tables, or photograph a handwritten page — QED converts your handwriting to clean LaTeX. No fighting with syntax to show what you know.

How practising Probability works

  1. Generate a fresh questionPick Probability and a difficulty — warm-up to build intuition, exam level for the real thing, or challenge for multi-step problems. A new, verified question appears in seconds.
  2. Answer in real notationType it, build it in the equation editor, lay out a truth table, or photograph your handwritten working and let QED convert it to LaTeX.
  3. Get marked criterion by criterionQED scores every rubric point separately, awards partial credit, flags where the reasoning slipped and shows a full model solution. The question is saved to your library to retake any time.

Related topics

Building a full picture of probability & counting? These pair naturally with Probability.

Probability — frequently asked questions

Is QED good for revising Probability before an exam?

Yes — that is exactly what it is built for. Generate probability questions at exam level (or push up to challenge), answer them under timed exam mode, and get marked against a rubric with a full model solution. You can retake any question and watch your Probability mastery climb until it is solid.

How many Probability questions can I practise?

As many as you like. QED generates fresh probability problems on demand instead of recycling a fixed set, and every question you make is saved to your library to retake for free. New accounts start with free question generations, no card required.

Do I need to know LaTeX to answer Probability questions?

No. There is a one-tap palette for symbols, a visual equation editor, and a truth-table builder — and you can photograph a handwritten solution and let QED convert it to LaTeX for you. You concentrate on the maths, not the typesetting.

Ready to make Probability exam-proof?

Generate your first probability questions free — no card, no setup, no personal data stored. Practise until it is second nature.

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