Answer the fundamental questions of economics and explain how growing cities and civilizations fostered markets and the move from barter to money

Learning goal: Explain the fundamental questions of economics — what to produce, how to produce and for whom to produce — and explain how the growth of cities and civilizations fostered the growth of markets and how market exchanges encouraged the transition from barter to monetary economies. This lesson teaches Ohio's 2026 social studies standards for Grade 5, published in July 2026. The Ohio Department of Education and Workforce anticipates that districts will begin implementing the 2026 standards in the 2027-28 school year.

Scarcity forces three questions. Every society has limited productive resources: land, water, workers, tools and time. People's wants are greater than what those resources can make. This problem is called scarcity, and it forces every society, from a family to an empire, to answer three fundamental questions of economics:

1. What to produce? Which goods and services should be made, and how much of each? Corn or cotton? Houses or roads?
2. How to produce? Which resources and methods should be used? Hand tools or machines? Many workers or a few?
3. For whom to produce? Who gets the goods and services once they are made? Those who pay? Those in charge? Everyone equally?

Societies answer these questions in different ways. In some, tradition decides: people make what their parents made, in the same way. In others, a ruler or government decides. In others, markets decide: buyers and sellers make their own choices, and prices guide what is produced and who receives it. Most societies mix these ways.

Two civilizations, two sets of answers. The Inca Empire of the Andes answered the three questions mainly through its rulers. Officials decided what crops and cloth should be produced, communities owed the state labor through a system called the mit'a, and goods were stored in state storehouses and given out to soldiers, workers and people in need. The Inca economy did not depend on money or large marketplaces. The Mexica (Aztec) of central Mexico also had a strong state that collected tribute, but everyday exchange took place in huge markets. Families decided much of what to produce for sale, and buyers who brought goods or money of value received what they chose. Both civilizations were large and successful, but they answered "for whom?" in different ways.

How growing cities fostered markets. Markets grow when three things come together. First, surplus: when farmers can grow more food than their own families need, some people are free to do other work. Second, specialization: those people become potters, weavers, toolmakers or merchants, and each must trade to get the things they do not make. Third, concentration: cities bring thousands of producers and buyers close together, so a regular meeting place for trade — a market — becomes worthwhile. In many civilizations, such as the Mexica, as cities grew so did their markets, though not every civilization followed this path (the Inca, described above, relied mainly on storehouses and labor service).

Spanish soldiers who visited the great market of the Mexica capital in 1519 described its size with amazement. In a letter to the king written in 1520, Cortés described a market square twice as large as the main square of the Spanish city of Salamanca; historians identify it with the market of Tlatelolco, the Mexica twin city of Tenochtitlan. Sellers there offered maize, beans, chiles, cloth, feathers, pottery, tools, animals and much more, arranged in sections, with officials who checked that measures were fair. A market that large was possible only because the city was so large.

Barter and its problem. The simplest exchange is barter: trading one good directly for another with no money involved. Barter works when two people each want exactly what the other has. That lucky match is called a double coincidence of wants. As markets grow and goods become more varied, the match becomes hard to find. Suppose a potter wants cloth, but the weaver wants fish, and the fisher wants pots. No two of them can trade directly. The potter might have to make several trades to get the cloth, wasting time.

The transition to money. Money solves the problem. Money is anything people generally accept in exchange for goods and services. It does three jobs: it is a medium of exchange (people in that community accept it for most purchases), a unit of account (prices can be stated in it, so goods are easy to compare) and a store of value (it can be saved for later, although its value can change and some kinds, such as cacao beans, can spoil). In Mexica markets, cacao beans and standard lengths of cotton cloth called quachtli worked as money: cacao for small purchases, cloth for larger ones. Because everyone accepted them, the potter could sell pots for cacao and use the cacao to buy cloth. Market exchanges therefore encouraged the move from barter to a monetary economy. A model, not a timeline every society followed. The steps in this lesson (surplus, specialization, growing cities, markets, money) are a simplified economic model that explains one reason people come to use money: it makes exchange in a busy market easier. It is not a sequence every society passed through. Barter, credit (a promise to pay later), gifts, tribute and goods handed out by rulers often existed alongside money, and the Inca built a great civilization that relied mainly on labor service and storehouses rather than money or large markets. Different societies used different forms of money at different times, often side by side: metal coins were used in parts of the Eastern Hemisphere by about 600 B.C.E., nearly two thousand years before the Mexica, and paper money and digital payments came later still. The jobs of money stayed the same.

The misconception. Students often think money must be coins or bills. Anything people generally accept can be money if it does the three jobs, which is why cacao beans could serve as money.

Worked example 1 — the three questions for a lemonade stand: What to produce: lemonade and, because of limited lemons, 40 cups. How to produce: hand-squeezed lemons, one pitcher, two workers. For whom: customers who pay 50 cents a cup, plus two free cups for the workers. The student notes that each answer used limited resources: lemons, time and workers.

Worked example 2 — the barter problem: Three hypothetical traders meet. Ana has pots and wants cloth. Ben has cloth and wants fish. Cai has fish and wants pots. Can any two trade directly so both get what they want? Ana and Ben: Ben does not want pots, so no. Ben and Cai: Cai does not want cloth, so no. Ana and Cai: Cai wants pots, but Ana wants cloth, not fish, so no. There is no double coincidence of wants. With money (Cai starts with 10 cacao beans): Ana sells a pot to Cai for 10 cacao beans; Ana buys cloth from Ben for 10 cacao beans; Ben buys fish from Cai for 10 cacao beans. Each person ends with what they wanted, and each ends with the same number of cacao beans they started with. Money made three trades possible.

Worked example 3 — surplus to market: A hypothetical village of 100 farming families can grow enough food for 130 families after better irrigation. The 100 farming families keep farming, and their extra food (130 − 100 = 30 families' worth) can feed about 30 more families who do not farm. They become potters, weavers and toolmakers. Now there are four kinds of producers who must trade, so a weekly market forms. As the town grows to thousands, the market meets every day and people begin using a common money. In this simplified model the chain is: surplus → specialization → city growth → market → money. Real societies did not all follow it, as the Inca show.

Economic questions and market flow chart (representation task): Draw a flow chart with five boxes: surplus food, specialized workers, growing city, market, money. Under each arrow, write one sentence explaining why, in this simplified model, one step leads to the next. Next to it, make a three-row table answering what, how and for whom to produce for one civilization you studied (Inca or Mexica).

Independent performance: Run a class market simulation in two rounds. In round one, trade only by barter using item cards; in round two, trade using a class money (such as paper "cacao" tokens). Record how many trades each person completed in each round. Then write 150–250 words. Success criteria: (1) you define barter, double coincidence of wants and money; (2) you compare your number of trades in the two rounds and explain the difference; (3) you name the three jobs money does and give an example of each from the simulation; (4) you explain how the growth of cities fostered markets using the words surplus and specialization; (5) you state how your class answered what, how and for whom to produce.