Mastery Questions
Write what you know. See exactly what's missing.
Written questions from your own chapter, each answer marked against the text's key points — what you hit, what you missed, what a stronger answer looks like.
Free account · One chapter or document · Your first written question in a couple of minutes
Application
1/2· 32A company already owns a warehouse it isn't using. Explain why the warehouse still has a cost, and what that cost is.
Tests whether opportunity cost survives the absence of a cash payment — the chapter's hardest idea to apply.
Your first answer sets your ceiling — retakes close half the gap.
The grade
You don't just get a score. You see what the answer left out.
Principles of MicroeconomicsExample notebook · illustrative
A company already owns a warehouse it isn't using. Explain why the warehouse still has a cost, and what that cost is.
Tests whether opportunity cost survives the absence of a cash payment — the chapter's hardest idea to apply.
Your answer
The warehouse still costs money because the company could rent it out to someone else instead of leaving it empty. The rent they're not collecting is the real cost of keeping it, even though they already own it.
Feedback
You wrote that the company "could rent it out to someone else" — that is the right instinct: the cost of keeping the warehouse is what keeping it gives up, and owning it doesn't cancel that. Where the answer stops short is the word "rent". Rent is one alternative; the opportunity cost is the best one the company could have chosen — renting, selling, or using the space itself — and you need that idea to explain why the cost exists even when no money changes hands at all. It is an implicit cost: nothing is paid, something is still lost. That is exactly why economists count it in economic profit while an accountant's ledger leaves it out. If the company sold the warehouse instead, what would the cost of keeping it become — and would it be larger or smaller than the rent?
This page
The feedback opens with the learner's own words. It marked what was written, not what it expected to read.
Right instinct; missed the implicit cost and the profit distinction.
Key points
- The cost is the best alternative use the company gives up — the opportunity cost
- Owning the warehouse does not make that cost disappear
- The cost exists even though no cash changes hands — an implicit cost
- Economic profit counts implicit costs; accounting profit does not
Treated renting it out as the only alternative — the opportunity cost is the best forgone option, whichever it is.
Attempts 1 · scores 58 · mastery 58
This page
The key points come from the material, before anyone answers. The marking says which ones the answer reached — 2 of 4, by name — and which it didn't.
Why the score
Rent was one alternative. The rule wants the best one — and the cost exists even when nothing is paid. Ritsu's answer opens only after the first attempt — so the answer is yours before it's anyone's.
Even though the company pays nothing to keep the warehouse, using it (or leaving it idle) has an opportunity cost: the value of the best alternative use it forgoes — renting the space to another firm, selling the building, or using it for its own storage. Ownership does not make that cost vanish; it only hides it, because no cash changes hands. Economists call this an implicit cost. It is why economic profit, which subtracts implicit costs as well as explicit ones, can be lower than accounting profit, which counts only the bills actually paid. The warehouse's cost is whatever the company's best alternative would have earned.
Your answer
The warehouse has a cost even though no cash changes hands: it's an implicit cost. Keeping it means giving up the best alternative use — renting it out, selling it, or using the space for the company's own storage — and owning it doesn't make that loss disappear. An accountant ignores it because nothing is paid, but an economist counts it, which is why economic profit is lower than accounting profit.
Feedback
Last time "rent" was doing all the work; this time you wrote that the cost exists even though "no cash changes hands" and named it as an implicit cost — that is the idea the first answer was missing, and you tied it to the best alternative use rather than to one alternative. The gap that remains is small but real: you list renting, selling and self-storage as options without saying which one sets the cost. Only the single best alternative counts; the others are not added up. Precision here is what separates a good answer from a complete one. Push it one step: if the best alternative changes next year, does the warehouse's cost change with it?
Complete mechanism; the profit distinction is now explicit.
Key points
- The cost is the best alternative use the company gives up — the opportunity cost
- Owning the warehouse does not make that cost disappear
- The cost exists even though no cash changes hands — an implicit cost
- Economic profit counts implicit costs; accounting profit does not
Attempts 2 · scores 58 → 88 · mastery 76
This page
The rewrite scored 88. Mastery didn't jump to 88: the first attempt set it at 58, and a retake closes half of what's left — so 76. That's the product's rule, and it's why the number is worth looking at twice.
A right idea can still be an incomplete answer.
Your answer can hold the core mechanism and still leave out half the reasoning.
A right/wrong result collapses that into one bit. A written grade shows which parts were there, which were absent, and where the reasoning went off course.
Right or wrong is one question. What exactly is missing is the useful one.
Free account · One chapter or document · Your first written question in a couple of minutes
Recognise vs produce
Recognising the answer is not the same as producing it.
Rereading can make an idea feel familiar. Multiple choice can tell you whether you recognise the right option. A written answer asks for something different:
Can you reconstruct the idea yourself — clearly enough for someone else to mark what is missing?
A company already owns a warehouse it isn't using. Explain why the warehouse still has a cost, and what that cost is.Example notebook · illustrative
Pick one
That is when the skipped step appears. The vague term. The missing condition.
The misconception that was invisible while the answer sat in front of you.
Don't stop at "I know it." Put it into words.
Sound familiar?
The practice should take the time. Not building the practice.
Maybe you've been doing this by hand:
- read the lecture
- decide what might be asked
- write your own questions
- write a marking scheme
- finally answer
Or you skip the questions because creating them takes too long.
Or you write answers — and have nobody to tell you whether they were actually complete.
The valuable work is producing the answer. The setup is not.
- Read the lecture
- Decide what might be asked
- Write your own questions
- Write a marking scheme
- Finally answer
Automate the questions. Keep the writing.
Not a quiz
Not a quiz you finish. A notebook you improve.
Principles of Microeconomics
Scarcity, choice and opportunity cost, the production possibilities frontier, and how supply and demand set prices. Distilled into 12 mastery questions to answer in your own words.
- 1FoundationFoundation of the pyramid: retrieve the facts, terms, and structure of this material from memory. Without retrieval, higher-order thinking has nothing to stand on.1/241
- 2UnderstandingMeaning-making: explain these ideas in your own words, see why one idea leads to the next, and connect examples to the concepts they illustrate.1/236
- 3ApplicationKnowledge in motion: use these methods, rules, and concepts on situations the document never showed you.1/232
- 4AnalysisTaking it apart: decompose arguments, trace causes to effects, and surface the assumptions holding everything up.0/2
- 5EvaluationJudgment with criteria: weigh the arguments, judge reliability, compare alternatives, and say where these ideas stop working.1/224
- 6Creation & SynthesisThe summit: combine these ideas into something new — a design, a plan, a teaching analogy, a hypothesis the document never stated.0/2
Mastery grows as you answer — untouched questions count as 0 inside their category.
Foundation
- List the three questions every economy must answer, in the order the chapter gives them, and say why the order matters.82
- Define opportunity cost as the chapter presents it — and name the property that separates it from a plain "cost".
Understanding
- The chapter opens by insisting that scarcity, not money, is the economic problem. In a sentence or two, what does the author most want you to take away from that?71
- In your own words: why is the production possibilities frontier bowed outward, not a straight line?
Application
- If the price of coffee beans doubles, predict what happens to the supply curve for coffee — and to the quantity supplied at last week's price.64
- A company already owns a warehouse it isn't using. Explain why the warehouse still has a cost, and what that cost is.
Analysis
- The chapter says a market "clears" at equilibrium. What assumptions is that claim quietly making?
- Trace the chain: a price ceiling is set below the equilibrium price. What happens, step by step, and why?
Evaluation
- Where does the supply-and-demand model stop working? Name one condition under which it gives a misleading answer, and why.47
- A headline says "Rent control keeps housing affordable." Judge that claim against the chapter.
Creation & Synthesis
- Explain opportunity cost to a twelve-year-old using a choice from their own week — without using the word "cost".
- Design a one-week experiment a café could run to find out whether its customers respond more to price or to queue length.
- One question tells you what the marking feels like.
- A full notebook shows where you stand across the material.
- Every question keeps its own answer, score and mastery — so the weak ones stay visible until you come back and improve them.
First attempt
— /100
mastery —
Second attempt
— /100
mastery —
The interesting number isn't the first score. It's the score you can improve.
A quiz gives you a percentage. This gives you an answer you can come back and beat.
How the marking works
A grade you can inspect.
The grading spine
- Key points from your material
- Your answer
- Hit / missed
- Misconception
- Ritsu's answer
Before you answer, Ritsu has already pulled the key points a complete answer must cover out of your material — up to six per question. You never see them first.
Your answer is read against that list: which points it reached, which it didn't, what it got wrong, and one score for the attempt. Then Ritsu's answer opens.
Improvement counts. Repetition doesn't game the score.
You can rewrite a weak answer. The first attempt sets the mastery; every retake adds half of what's left, scaled by how well you did. The number never goes down — so a rewrite can't cost you anything, and a weak first answer takes several strong rewrites to climb back.
From a first attempt of 58
mastery becomes
76 /100
58 + half of the remaining 42, × 88%
and a third attempt at the same score
87 /100
Half of what's left, every time — the climb gets slower the closer you get.
Why the grade
You can see why the answer got the grade it did.
The key points come from your material
Up to six per question, pulled from the text before you answer and revealed only after your first attempt. Nothing generic — the reference is the chapter you're studying.
One score, and the reasons
Every graded answer gets one score from 0 to 100, a one-line summary, and the misconceptions named. Answers under 40 characters are capped; under 20, nothing is sent at all.
Progress that survives a second look
The first attempt sets a question's mastery. Each rewrite adds half of what's left, scaled by its score. The number never goes down, a question ticks at 75, and your last ten attempts stay on record.
Mastery Questions shows what you can produce. Ritsu turns the gaps into what to learn next.
Your notebook already knows which answers are strong, which are thin, and which questions are still blank. Ritsu runs the wider loop around them — and brings the weak ideas back before they fade.
- Understand
- Retrieve
- Practice
- Get feedback
- Review
- Master
Questions
What people ask before their first answer.
About three or four lines is enough to start. The tool won't send anything under 20 characters, caps the score of anything under 40, and asks before sending a first answer under 200 — because the first answer sets the ceiling. Plain text is fine; there's a rich editor for markdown and math when you need it.
One more time
Stop making the questions. Start writing the answers.
Use something you actually need to know.
Ritsu turns it into a notebook of written questions, then marks every answer you produce — what you got, what you missed, and what to improve next.
Free account · One chapter or document · Your first written question in a couple of minutes
- File
- YouTube
- Website
- Paste text
Your words. Your gaps. Your next attempt.