# Choose an economics introduction and test a policy claim — Study worksheet

[Study guides](https://unireadinglist.com/guides/economics-foundations/)

[Course topic: Principles of Economics](https://unireadinglist.com/subjects/economics/#course-principles-of-economics)

Sources checked: 2026-11-03

Study route and exercise: University Reading List editorial project.

This route serves beginners who can rearrange a linear equation and read a graph. It compares OpenStax Principles of Economics 3e, Mankiw’s tenth edition and CORE’s The Economy 2.0: Microeconomics. The six outputs and numerical case are this site’s study suggestions, not an official syllabus, a demand estimate or advice on an actual tax policy.

## Choose your starting point

- [ ] I need a free micro-and-macro foundation
  Use OpenStax as the main spine. Read the assigned sections and produce the outputs below; a freely available book is useful only if you practise drawing, calculating and explaining.

- [ ] My class prescribes Mankiw’s tenth edition
  Follow that edition and your lecturer’s assignment numbers. Check whether a book, an eText entitlement or a separate MindTap product is required before paying; matching a title alone is insufficient.

- [ ] I want institutions and inequality near the start
  Choose CORE for a microeconomics route that connects decisions to institutions. Pair it with OpenStax’s macro chapters when you need national-income measurement; this selected CORE volume does not cover an entire micro-and-macro sequence.

## Compare the three books

### Principles of Economics 3e

Steven A. Greenlaw; David Shapiro; Daniel MacDonald · 3 · 2022
Free broad-course anchor

Choose it when: You need an accessible reference across household decisions, markets and the macroeconomy, and can organize your own practice.
Use another route when: A course requires another edition’s graded questions, or your immediate question needs advanced causal identification.
Selected reading: Chapters 1–3 and 5 establish choices, equilibrium and elasticity; 7–9, 12–13 develop firms and market failures; 19, 21–22 begin macro measurement.
Limits and trade-offs: The authorized web/PDF is free to read. Do not infer unrestricted commercial reuse from free access, or treat a numerical illustration as measured evidence about a local market.

#### Try before choosing

Use OpenStax’s market chapter to solve the invented equations Qd=12−P and Qs=P, then draw the equilibrium with units.
Check your work: P=6 and Q=6 satisfy both curves. A movement along a curve is distinguished from a shift, and neither equation is called an estimate of a real market.

Your notes:

________________________________

ISBN: 9781711471457

[Official free reading](https://openstax.org/details/books/principles-economics-3e)

[Book record and access options](https://unireadinglist.com/subjects/economics/principles-of-economics-openstax/)

### Principles of Economics

N. Gregory Mankiw · 10 · 2024
A prescribed-course alternative

Choose it when: Your course actually adopts the tenth edition, or you want one consistent micro-and-macro structure and its assigned practice.
Use another route when: You already have a suitable introduction and no assignment depends on this edition; buying another survey need not improve your explanation.
Selected reading: Use 1–8 for the first tools, 10–11 and 14–16 for failures and firms, then 24–25 and 29 for income, prices and unemployment.
Limits and trade-offs: The publisher identifies the selected book as ©2024. Its book ISBN and MindTap access ISBNs are different products. Chapter 12 is healthcare, so later numbering differs from earlier editions.

#### Try before choosing

Use Mankiw’s introductory opportunity-cost/equilibrium route to explain why the identity of the tax remitter cannot by itself establish economic incidence. Add a diagram with separate buyer and seller prices.
Check your work: The diagram labels a tax wedge and traded quantity. The explanation names the supply/demand responses needed; “the seller pays the authority” is not offered as the entire incidence argument.

Your notes:

________________________________

ISBN: 9780357722718

[Book record and access options](https://unireadinglist.com/subjects/economics/principles-of-economics-mankiw/)

### The Economy 2.0: Microeconomics

The CORE Econ Team · 2.0 · 2024
Problem-led microeconomics and institutions

Choose it when: You want to ask whose options and bargaining power a model assumes, while learning the model itself.
Use another route when: You need a complete macroeconomics textbook or a direct substitute for a prescribed conventional problem set.
Selected reading: Units 2–3 cover incentives and scarcity; 5 concerns institutional rules, 7 firms, 8 competitive markets and 10 private decisions with societal effects.
Limits and trade-offs: Use this microeconomics volume deliberately. The shared CORE landing page also links a separate macro volume; its existence does not make it part of the selected print book or this guide’s chapter map.

#### Try before choosing

After CORE unit 8, write a two-column model audit for the same market: rules/assumptions and observations needed to assess them. Include whether suppliers can change quantity.
Check your work: Price-taking and quantity responsiveness are explicit assumptions, not natural facts. Your audit identifies one measurement that could reject the assumed supply response before drawing a distributional conclusion.

Your notes:

________________________________

ISBN: 9781647921606

[Official free reading](https://books.core-econ.org/the-economy/microeconomics/0-3-contents.html)

[Book record and access options](https://unireadinglist.com/subjects/economics/the-economy-2-0-microeconomics/)

## Check your preparation

### What is the opportunity cost of a free afternoon?

Your notes:

________________________________

### Does a rise in quantity demanded prove that demand shifted?

Your notes:

________________________________

### Can a correct equilibrium calculation settle whether a policy is fair?

Your notes:

________________________________

## Six steps with a concrete output

- [ ] 1. Define a choice before drawing a market

Selected reading: OpenStax 1–2; Mankiw 1–3; CORE 2–3.

Make this: Write a 150-word account of one fictional time or budget choice. Identify the decision maker, constraint, best forgone alternative and one claim about what ought to happen.

Check your work: A reader can distinguish the feasible alternatives, opportunity cost and value judgment. Label any invented numbers rather than presenting them as observations.

Your notes:

________________________________

- [ ] 2. Build a market you can solve

Selected reading: OpenStax 3; Mankiw 4; CORE 8.

Make this: Draw and solve one linear supply-and-demand model with named axes and units. Then shift demand while leaving supply fixed, and explain why that differs from a movement along demand.

Check your work: The graph and algebra predict the same direction. Substitution into both original equations gives the same quantity, and the explanation names what changed.

Your notes:

________________________________

- [ ] 3. Separate statutory tax from economic burden

Selected reading: OpenStax 5; Mankiw 5–8; CORE 8 for the competitive baseline.

Make this: Complete the original tax example below. Make a table for buyer price, seller receipt, quantity, government revenue and lost surplus; identify each comparison with the no-tax baseline.

Check your work: The price wedge equals the tax. Revenue is tax times traded quantity, not the buyer’s entire payment. Explain why the party remitting the tax need not bear all of it.

Your notes:

________________________________

- [ ] 4. Change one institutional assumption

Selected reading: OpenStax 7–9 and 12–13; Mankiw 10–11 and 14–16; CORE 5, 7 and 10.

Make this: Write two short alternatives to your competitive model: one with a firm that can influence price, another with an external effect. State which earlier conclusion cannot simply be carried over.

Check your work: Each alternative changes a specific assumption rather than renaming the same diagram. A market outcome, an efficiency criterion and a fairness judgment are kept distinct.

Your notes:

________________________________

- [ ] 5. Audit a macroeconomic headline

Selected reading: OpenStax 19, 21–22; Mankiw 24–25 and 29; CORE 1 only for context.

Make this: Create a fictional headline using nominal spending and a price index, then rewrite it using the distinction between real and nominal quantities. Identify a population or activity the chosen measure leaves out.

Check your work: The units, base period and denominator are stated. A national aggregate is not silently treated as the experience of every household; CORE’s context is not substituted for a complete macro reading.

Your notes:

________________________________

- [ ] 6. Write a bounded conclusion with a reversal condition

Selected reading: Revisit OpenStax 2 and 18, Mankiw 2 and 37, or CORE 5 and 10.

Make this: Produce a one-page policy note with the problem, model, numerical result, distributional effects, omitted considerations and the next evidence to collect. Add one finding that would change your conclusion.

Check your work: Someone can reproduce the calculation and identify which sentence is descriptive and which is evaluative. Do not turn the invented case into a recommendation for a real jurisdiction.

Your notes:

________________________________

## Worked exercise: Who bears a tax that sellers remit?

In an invented competitive market, daily demand is Qd = 100 − 2Pb and supply is Qs = 2Ps. Prices are currency units per item; Q is items per day. Compare no tax with a tax of 10 per traded item remitted by sellers.

Assumptions: Treat the curves as exact for this exercise, with price-taking, market clearing, no external effects, no evasion and no other distortions. Pb is the buyer price and Ps the seller’s net receipt. Standard surplus triangles are used. Nothing here estimates an actual market.

Your notes:

________________________________

## Change an assumption: What if supply cannot change within this interval?

Replace the original supply Qs=2Ps by a fixed Qs=50 items/day for taxes 0≤t≤10. Retain demand Qd=100−2Pb, price-taking, no external effects/evasion and seller remittance. Find buyer price, seller receipt, quantity and tax revenue at t=10. Do not import the original supply curve’s cost or surplus triangles.

Your notes:

________________________________

## Before moving on

- You can select one main introduction and explain whether you need micro only, micro plus macro, or a prescribed course product.
- You can solve and graph the tax case, keep price and quantity units consistent, and distinguish a transfer from lost gains from trade.
- Your final note states assumptions, missing evidence and a conclusion-reversal condition rather than presenting a textbook model as a forecast.

## Answer and interpretation

### What is the opportunity cost of a free afternoon?

The value of the best feasible alternative you give up, even if no money changes hands. State the alternative instead of automatically counting every forgone activity.

### Does a rise in quantity demanded prove that demand shifted?

No. A lower own price can move you along an unchanged demand curve. A shift requires a changed condition such as income or preferences, with the relevant other conditions held fixed.

### Can a correct equilibrium calculation settle whether a policy is fair?

No. The calculation is conditional on a model. Distribution, values, missing effects and how revenue is used require separate arguments and evidence.

### Who bears a tax that sellers remit?

1. Without tax, Pb = Ps = P. Solve 100 − 2P = 2P: P = 25 and Q = 50.
2. With the tax, Pb = Ps + 10. Then 100 − 2(Ps + 10) = 2Ps, so Ps = 20, Pb = 30 and Q = 40.
3. Buyers pay 5 more and sellers receive 5 less per item. The equal split follows from these curves, not from a universal rule about who pays taxes. Government revenue is 10 × 40 = 400 per day.
4. Before tax, consumer and producer surplus are each ½ × 25 × 50 = 625. After tax, each is ½ × 20 × 40 = 400. Including tax revenue, modeled total surplus falls from 1,250 to 1,200.
5. The 50 difference also equals the deadweight-loss triangle: ½ × tax wedge 10 × quantity reduction 10. Tax revenue is a transfer within this accounting, not itself the deadweight loss.

The seller-remitted tax raises the buyer price to 30, lowers the seller receipt to 20 and reduces daily trade to 40. Modeled deadweight loss is 50. This result does not include benefits from spending the revenue or any external costs the tax might address.

Test the result: Set the tax to zero and recover the original equilibrium. As a sensitivity check, tax 20 gives Pb = 35, Ps = 15 and Q = 30; the triangle loss becomes 200. Real incidence requires evidence about behavior and alternatives, not these invented slopes.

### Change an assumption: What if supply cannot change within this interval?

1. Market clearing requires 100−2Pb=50, hence Pb=25, unchanged from the untaxed fixed-supply equilibrium.
2. The wedge gives Ps=Pb−10=15. Quantity remains 50 items/day, so revenue is 10×50=500 currency units/day.
3. Before tax the seller received 25; now 15. Buyers pay no more in this stated interval, and sellers bear the full 10 per item. The old equal split relied on the replaced upward-sloping supply curve.

Pb=25, Ps=15, Q=50 and revenue 500/day. This counterexample refutes a universal fifty-fifty incidence rule, but does not estimate actual sellers’ options or the effects of spending tax revenue.

Test the result: Set t=0 and recover Pb=Ps=25. Do not extrapolate beyond the stipulated 0–10 range. The old producer-surplus formula assumed a different supply curve; the new fixed quantity alone does not specify every production cost or welfare component.

## Common mistakes

### Matching chapter numbers across editions

Mankiw’s tenth edition includes healthcare at chapter 12; use the stated tenth-edition map. A familiar title or an older online solution set does not establish that the question numbers match.

### Using a model’s assumptions as empirical findings

A competitive curve exercise assumes behavior and market structure. Before applying it, ask what observations support the slopes, market boundary and adjustment period.

### Calling a transfer a social loss

Keep buyer payments, seller receipts, government revenue and surplus changes in separate columns. Then explain the welfare criterion and anything omitted from it.

## Sources and edition checks

- [OpenStax — third-edition preface, scope and free formats](https://openstax.org/books/principles-economics-3e/pages/preface)
  The official third-edition preface confirms its broad micro/macro scope and authorized free web/PDF formats. It also states a noncommercial share-alike license; free reading is not an unrestricted reuse claim.

- [Cengage — Mankiw tenth-edition identity and separate access products](https://www.cengage.com/c/principles-of-economics-10e-mankiw/9780357722718/)
  The US publisher identifies the tenth edition as ©2024, the book ISBN 9780357722718 and separate digital-course products. Product prices are not used in this guide.

- [Cengage Australia — same-ISBN tenth-edition contents](https://au.cengage.com/c/principles-of-economics-10e-mankiw/9780357722718/?filterBy=Higher-Education)
  Cengage’s regional page for the same book ISBN supplies the complete chapter sequence, including chapter 12 healthcare and chapter 24 national income. Its release-date display and copyright year are separate facts.

- [CORE Econ — The Economy 2.0 Microeconomics contents](https://books.core-econ.org/the-economy/microeconomics/0-3-contents.html)
  The official microeconomics contents establish units 1–10 and their order. The six tasks, numerical market and judgments about what to read first are this site’s original study suggestions.

- [Hackett — microeconomics print edition identity](https://hackettpublishing.com/full-catalog/the-economy-2-0-microeconomics)
  The publisher’s indexed catalogue identifies the April 2024 paper edition, ISBN 9781647921606. Direct requests returned HTTP 403 during this check; the indexed record supports stable edition identity, not a claim about current stock or price.

These are proposed study activities, not official course assignments or a claim that every book has been read cover to cover.

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