In simple terms
A friendly intro before the formal notes — no formulas yet.
The market system
A market is wherever buyers and sellers trade. Prices rise when a product is scarce and fall when it is plentiful, and those price changes steer resources to where they are wanted without anyone planning it.
A busy food court has no manager telling stalls what to cook. The stall with the longest queue raises its prices and opens a second counter; the stall nobody visits cuts prices or changes its menu. Prices and queues do the organising.
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Buyers bring demand and sellers bring supply; they meet at a price.
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A shortage pushes the price up; a surplus pushes it down.
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Price changes signal, give incentives and ration — the price mechanism.
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Microeconomics studies single markets; macroeconomics studies the whole economy.
Explore the concept
Use the live diagram and synced steps — play it or tap a step card to walk through.
1 more simulation for this topic — run them in the Simulations section below
Simulations
Every simulation here runs the real model — try the steps on a card, then check what you see against the notes.
1 simulation
- GeoGebra2281 2.1
Supply and demand: shifts and surpluses
Demand and supply lines with DemandShift and SupplyShift sliders and tick boxes for shortage, surplus, revenue and consumer and producer surplus.
Try this
- Tick Show Shortage: at a price below equilibrium buyers want more than sellers offer.
- Tick Show Surplus: at a price above it sellers offer more than buyers want.
- Raise demand with the DemandShift slider and watch price P1 rise: the signal that draws more resources into this market.
Look for In a market system nobody plans output: changes in price ration what is scarce and signal where resources should move.
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At a glance — side by side
Compare key properties side by side — ideal for exam contrasts.
Microeconomics and macroeconomics
| Feature | Microeconomics | Macroeconomics |
|---|---|---|
| Scale | Individual markets, firms and households | The whole economy |
| Typical questions | Why has the price of rice risen? Should a firm expand? | Why is unemployment rising? Is inflation too high? |
| Prices studied | The price of one product or wage in one occupation | The general price level and the exchange rate |
| Syllabus sections | Sections 2 and 3 | Sections 4 and 5 |
| Government role | Taxes, subsidies and regulation in particular markets | Fiscal, monetary and supply-side policy for the economy |
Scale
Microeconomics
Macroeconomics
Typical questions
Microeconomics
Macroeconomics
Prices studied
Microeconomics
Macroeconomics
Syllabus sections
Microeconomics
Macroeconomics
Government role
Microeconomics
Macroeconomics
Full topic notes
Formal explanation with the rigour you need for the exam.
What is a market?
A market is any arrangement that brings buyers and sellers of a product together so that they can trade. It need not be a physical place: the foreign exchange market, the market for streaming subscriptions and the labour market all exist mostly online or on paper. What makes a market is the exchange, not the location.
In every market demand comes from buyers and supply from sellers, and the two meet at a price. When buyers want more than sellers offer, price rises; when sellers offer more than buyers want, price falls. The price that balances the two is the equilibrium price.
A market is any arrangement in which buyers and sellers trade a product — physical or not.
Buyers provide demand, sellers provide supply, and price brings them together.
The equilibrium price is the price at which quantity demanded equals quantity supplied.
Examples: goods markets, labour markets, financial markets, housing markets.
How the market system coordinates decisions
In a market system nobody plans production as a whole. Instead, prices carry information. A rise in the price of coffee tells farmers that consumers value coffee more, gives them an incentive to grow more, and rations the existing crop to the buyers willing to pay. These are the signalling, incentive and rationing functions of price, and together they are called the price mechanism.
The result is that resources move towards the goods people want most. A shortage of electricians raises electricians' wages, attracting more people to train; a fall in demand for printed newspapers lowers their price and profit, so paper mills and printers shift to other work. The price mechanism is studied in detail in topic 2.2.
The price mechanism is the way prices allocate resources without central planning.
Signalling: price changes tell producers and consumers what is scarce or plentiful.
Incentive: higher prices raise profits and draw resources into a product; lower prices push them out.
Rationing: when supply is limited, price rises so that only those willing to pay obtain the good.
If a question asks how a market 'responds' to an event, walk through the price mechanism in order: the shock changes demand or supply → price changes → producers and consumers react → resources are reallocated.
Microeconomics and macroeconomics
Microeconomics studies individual markets and decision makers: how one household spends its income, how the price of rice is set, whether a firm should expand. Macroeconomics studies the economy as a whole: total output, the general price level, unemployment, international trade and government economic policy.
The two are linked. Macroeconomic conditions such as a recession change the demand in individual markets, and the behaviour of millions of households and firms adds up to the macroeconomy. Sections 2 and 3 of the 2281 syllabus are microeconomics; sections 4 and 5 are macroeconomics.
Microeconomics: individual markets, consumers, workers and firms.
Macroeconomics: the whole economy — growth, inflation, unemployment, trade, government policy.
A change in the price of petrol is micro; a rise in the general price level (inflation) is macro.
Micro decisions add up to macro outcomes, and macro conditions shape micro markets.
Three questions and three systems
Because resources are scarce, every society must decide what to produce, how to produce it and for whom. Economic systems differ in who answers these questions. In a market economy private individuals and firms decide, guided by prices and profit. In a planned (command) economy the government owns most resources and decides centrally. In a mixed economy both the private sector and the public sector play a part.
Almost every real economy is mixed; they differ in the balance. The United States and Singapore leave more to markets, while Cuba and North Korea plan most production. Topics 2.9 and 2.11 examine the market system and the mixed system in depth.
Every economy must answer what, how and for whom to produce.
Market economy: private ownership, decisions made through prices and profit.
Planned economy: state ownership, decisions made by central planners.
Mixed economy: private and public sectors together; nearly every real economy.
Keep 'market' (a place where a product is traded) and 'market economy' (a whole system that relies on markets) distinct. Paper 1 likes to test the difference with a definition question.
Worked examples
See the formulas applied — reveal one step at a time, like the exam.
The table shows the weekly market for bread in a town.
| Price ($) | Quantity demanded | Quantity supplied |
|---|---|---|
| 1.00 | 5 000 | 2 000 |
| 1.50 | 4 000 | 3 000 |
| 2.00 | 3 500 | 3 500 |
| 2.50 | 3 000 | 4 000 |
(a) State the equilibrium price and quantity. (b) Explain how the market would react if bakers charged $1.00. (c) State whether this question is microeconomic or macroeconomic, and why.
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Step 1 — Equilibrium (a): quantity demanded equals quantity supplied at $2.00, where 3 500 loaves are traded each week.
Classify each of the following as microeconomics or macroeconomics, giving a reason:
(a) The government raises the rate of income tax to reduce inflation. (b) A fall in the price of cocoa reduces the incomes of cocoa farmers. (c) Unemployment in a country rises from 5% to 7%. (d) A supermarket cuts the price of milk to attract customers.
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Step 1 — (a) Macroeconomics. Income tax and inflation are economy-wide variables; the policy aims at the general price level, not one market.
How it all connects
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Tap a linked idea to see how it connects back to the main topic — that connection is what examiners reward.
Glossary
Key terms for this topic — skim now; the Check step will test them.
- market
A market is any arrangement that brings buyers and sellers of a product together so that they can trade.
- Price mechanism
The way changes in price allocate resources between competing uses without central planning.
- Signalling function of price
Price changes tell producers and consumers what has become more or less scarce.
- Incentive function of price
Higher prices raise profits and encourage producers to supply more; lower prices do the opposite.
- Rationing function of price
When supply is limited, price rises so that the good goes to the buyers willing and able to pay.
- Microeconomics
The study of individual markets and decision makers — households, workers and firms.
- Macroeconomics
The study of the economy as a whole — output, inflation, unemployment, trade and government policy.
- Three basic economic questions
What to produce, how to produce it, and for whom to produce it.
- Market economy
An economic system in which privately owned firms and individuals decide what to produce, guided by prices and profit.
- Planned economy
An economic system in which the government owns most resources and central planners decide what to produce.
Sort it out
One statement at a time, say which heading it belongs under. Every statement comes from this lesson’s side-by-side comparison.
The whole economy
Quick check
Write your answer first, then compare it with the model one — the gap is what you would have lost.
Teach it back
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Teach it back
Explain this topic as if teaching a friend. We name the gaps an examiner would still dock.
Revision flashcards
Guess first, then flip — retrieval beats re-reading.
Key takeaways
Review these before you close the topic — retrieval beats re-reading.
A market is any arrangement in which buyers and sellers trade a product — physical or not.
Buyers provide demand, sellers provide supply, and price brings them together.
The equilibrium price is the price at which quantity demanded equals quantity supplied.
Examples: goods markets, labour markets, financial markets, housing markets.
Practice — then mark it
The whole point: a real Cambridge question, marked mark-by-mark.
Mark a market system question
Mark a market system question
Extra simulations & links
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Frequently asked
Checkpoint
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Reading it isn’t knowing it — prove it.
Before you move on: do Mark a market system question on paper, snap a photo, and get examiner-style feedback on exactly where you win and lose marks.
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