Money does four jobs in an economy, and each job can be shown in a real exchange. To explain a function, name it, then point to the moment in the story where it happens. This lesson builds that habit with one example, and it feeds into the rest of money, banking and households.
Why does an exchange make the functions easier to see?
A list such as “medium of exchange, unit of account, store of value, standard of deferred payment” is easy to memorise and easy to forget. A story fixes it. When a single exchange carries all four functions, you can tell them apart by asking what the money is doing at each step.
Start with barter. Barter means swapping goods directly, with no money. It only works if each person has what the other wants, which is called a double coincidence of wants.
Worked example: Dewi and the bicycle pump
Dewi grows rambutan in a fictional village market. She has 40 kg to sell and wants a bicycle pump. The pump seller, Faizal, does not want fruit. He wants fish.
Step 1, barter fails. Dewi has fruit, Faizal wants fish, so there is no double coincidence of wants. She would have to trade fruit for fish first, then fish for the pump. That costs time and each swap may lose value.
Step 2, medium of exchange. Dewi sells her 40 kg to a trader at RM6 per kg. She receives 40 × 6 = RM240. Money is accepted by both sides, so the trade is finished in one step. This is the medium of exchange function.
Step 3, unit of account. The pump is priced at RM45. Dewi can compare it with her fruit: 45 ÷ 6 = 7.5, so the pump costs the same as 7.5 kg of rambutan. Prices in one unit let her compare goods that have nothing in common. This is the unit of account function.
Step 4, store of value. Dewi pays RM45 for the pump and keeps RM195 (240 − 45) for the week. Rambutan would rot, but the money keeps its purchasing power for later. This is the store of value function. It is not perfect, because rising prices would reduce what RM195 can buy.
Step 5, standard of deferred payment. Faizal lets Dewi buy a tyre repair kit for RM30 now and pay in 30 days. The amount owed is stated in money, so both sides know what is due. This is the standard of deferred payment function.
| Function | Where it appeared | Figure |
|---|---|---|
| Medium of exchange | Fruit sold for money | RM240 |
| Unit of account | Pump compared with fruit | 7.5 kg of rambutan |
| Store of value | Money kept for the week | RM195 |
| Deferred payment | Repair kit paid in 30 days | RM30 |
Check the balance: RM240 received, RM45 spent on the pump, RM195 kept. The RM30 owed is a future payment, so it is not part of today’s cash.
The mistake to watch for
A common slip is to name a function and then give a story that shows a different one.
Mistaken answer: “Money is a store of value because Dewi uses RM240 to buy a pump.”
Buying the pump is money being accepted in exchange. That is the medium of exchange function.
The correction is to match the verb to the function.
Accepted in payment means medium of exchange. Used to compare prices means unit of account. Kept for later means store of value. Owed in the future means deferred payment.
Check yourself
Cover the answers and write your response first.
1. Najwa sees a shirt at RM35 and a cap at RM14 and decides the shirt is better value. Which function of money helps her compare them?
Show answer
Unit of account. Both goods have prices in the same unit, so she can compare them. The shirt costs 35 ÷ 14 = 2.5 times the cap.
2. Karthik pays RM1,200 in school fees by instalment, RM400 each month for three months. Which function is shown by the agreed amounts?
Show answer
Standard of deferred payment. The amount owed in the future is stated in money. Three payments of RM400 give 3 × 400 = RM1,200, so the total is consistent.
3. Why is money a better store of value than fresh fruit for one week, and what weakens it?
Show answer
Fresh fruit spoils, but money keeps its value as something that can be spent later. The function is weakened if prices rise, because the same RM amount then buys fewer goods.
Where this leads next
Next, separate two ideas that students often blur: saving and investment in the syllabus sense. When you have finished the module, test yourself with the mixed practice set. The percentage-base explorer helps when a question mentions price rises.
Some students know the four functions but lose marks when an example is requested. That is a skill our teachers coach in online one-to-one Economics tuition.