📚 Year 8 AQA Economics Formula & Principles Quick Reference Handbook | AQA 经济：公式定理速查手册
Welcome to your Year 8 AQA Economics quick reference guide. This handbook collects the essential formulas, definitions, and economic principles you will meet in Key Stage 3. Each section explains one idea clearly, with a formula where appropriate, and the same explanation repeated in Chinese to help bilingual learners build confidence. Keep this page bookmarked for homework, revision, and mini-tests.
欢迎使用你的八年级 AQA 经济速查手册。这本手册汇集了你在 KS3 阶段会学到的重要公式、定义和经济原理。每一节先解释一个概念，需要公式的地方给出公式，并用中文重复解释，帮助双语学习者建立信心。收藏本页，随时用于作业、复习和小测验。
1. Opportunity Cost | 机会成本
Opportunity cost is the value of the next best alternative you give up when you make a choice. Because resources are scarce, every decision involves a trade-off. For example, if you spend an hour studying economics instead of playing football, the opportunity cost is the enjoyment and fitness gain from football.
机会成本是你做出选择时放弃的次优选项的价值。由于资源是稀缺的，每个决定都涉及权衡取舍。例如，如果你花一小时学习经济而不是踢足球，机会成本就是踢足球带来的乐趣和锻炼收益。
Opportunity Cost = Value of the Next Best Alternative Forgone
机会成本 = 放弃的次优选择的价值
2. Factors of Production | 生产要素
Economists group resources into four factors: land (natural resources), labour (human effort), capital (man-made goods used to produce other goods), and enterprise (the ability to combine the other factors and take risks). Remember the acronym C-E-L-L: Capital, Enterprise, Land, Labour.
经济学家将资源分为四种生产要素：土地（自然资源）、劳动（人力付出）、资本（用于生产其他商品的人造物品）和企业家才能（组合其他要素并承担风险的能力）。记住缩写 C-E-L-L：资本、企业家才能、土地、劳动。
| Factor 要素 | Examples 例子 | Reward 报酬 |
|---|---|---|
| Land 土地 | Oil, forests, water 石油、森林、水 | Rent 租金 |
| Labour 劳动 | Teachers, builders 老师、建筑工人 | Wages 工资 |
| Capital 资本 | Machines, tools 机器、工具 | Interest 利息 |
| Enterprise 企业家才能 | Start-up founder 创业家 | Profit 利润 |
3. Scarcity and Choice | 稀缺与选择
Scarcity means there are limited resources to meet unlimited wants. The basic economic problem forces individuals, businesses, and governments to make choices. Because we cannot have everything, we must decide what to produce, how to produce, and for whom to produce it.
稀缺意味着有限的资源无法满足无限的欲望。这个基本经济问题迫使个人、企业和政府做出选择。因为我们无法拥有一切，所以必须决定生产什么、如何生产以及为谁生产。
Scarcity → Choice → Opportunity Cost
稀缺 → 选择 → 机会成本
4. Demand | 需求
Demand represents how much of a good or service consumers are willing and able to buy at different prices over a given time. The law of demand states that, ceteris paribus, as the price of a good rises, the quantity demanded falls, and vice versa. This inverse relationship creates a downward-sloping demand curve.
需求表示消费者在一定时期内、在不同价格水平下愿意并且能够购买的商品或服务数量。需求定律指出，在其他条件不变的情况下，商品价格上升，需求量下降，反之亦然。这种反向关系形成了一条向下倾斜的需求曲线。
Law of Demand: P ↑ → Qd ↓
需求定律：价格 ↑ → 需求量 ↓
5. Supply | 供给
Supply is the quantity of a good or service producers are willing and able to offer for sale at each price over a period. The law of supply says there is a positive relationship between price and quantity supplied: when price increases, the quantity supplied rises, other things being equal. The supply curve typically slopes upward.
供给是生产者在一定时期内、在各种价格水平下愿意并且能够提供出售的商品或服务数量。供给定律指出价格与供给量之间为正相关：价格上升，供给量增加，其他条件不变。供给曲线通常向上倾斜。
Law of Supply: P ↑ → Qs ↑
供给定律：价格 ↑ → 供给量 ↑
6. Market Equilibrium | 市场均衡
Equilibrium occurs where the quantity demanded equals the quantity supplied at a given price. This is the 'market clearing' point. If the price is too high, a surplus occurs (Qs > Qd); if too low, a shortage results (Qd > Qs). Prices tend to move towards equilibrium naturally in a free market.
均衡出现在需求量等于供给量的价格点上。这是市场出清点。如果价格过高，会出现过剩（供给量大于需求量）；如果价格过低，会出现短缺（需求量大于供给量）。在自由市场中，价格趋向于自发移向均衡点。
Equilibrium: Qd = Qs
均衡：需求量 = 供给量
7. Price Elasticity of Demand (PED) – Basic Idea | 需求价格弹性 – 基本概念
PED measures how responsive the quantity demanded is to a change in price. For KS3, it is enough to know that some goods are price elastic (demand changes a lot when price changes – e.g. luxury snacks) and some are price inelastic (demand changes little – e.g. essential medicines). The formula is simplified as:
需求价格弹性衡量需求量对价格变动的反应程度。在 KS3 阶段，只需知道有些商品富有价格弹性（价格变动时需求量变化很大——例如奢侈零食），有些商品缺乏价格弹性（需求量变化不大——例如必需药品）。简化公式为：
PED = % Change in Quantity Demanded ÷ % Change in Price
需求价格弹性 = 需求量变动的百分比 ÷ 价格变动的百分比
If PED > 1, demand is elastic. If PED < 1, demand is inelastic.
如果 PED > 1，需求富有弹性；如果 PED < 1，需求缺乏弹性。
8. Total Revenue | 总收益
Total revenue is the income a firm receives from selling its products. It is calculated by multiplying the price per unit by the quantity sold. The link with PED is important: if demand is elastic, raising price may lower total revenue; if inelastic, raising price tends to raise total revenue.
总收益是企业从销售产品中获得的收入，由单位价格乘以销售数量得出。它与需求价格弹性的关系很重要：如果需求富有弹性，提高价格可能降低总收益；如果需求缺乏弹性，提高价格往往会增加总收益。
Total Revenue (TR) = Price (P) × Quantity (Q)
总收益 = 价格 × 数量
9. Costs: Fixed, Variable and Total | 成本：固定成本、可变成本与总成本
Fixed costs (FC) do not change with output, e.g. rent. Variable costs (VC) change directly with output, e.g. raw materials. Total cost (TC) is the sum of fixed and variable costs. Understanding costs helps a business decide how much to produce.
固定成本（FC）不随产量变化，例如租金。可变成本（VC）直接随产量变化，例如原材料。总成本（TC）是固定成本与可变成本之和。了解成本有助于企业决定生产多少。
TC = FC + VC
总成本 = 固定成本 + 可变成本
Average cost (AC) or unit cost is TC ÷ Q. Profit = TR − TC.
平均成本或单位成本 = 总成本 ÷ 数量。利润 = 总收益 − 总成本。
10. The Economic Problem: What, How, For Whom | 经济问题：生产什么、如何生产、为谁生产
Every society must answer three fundamental questions because of scarcity. What goods and services should be produced? How should they be produced, using which combinations of factors? For whom are they produced – that is, who gets to consume them? Different economic systems (market, command, mixed) answer these differently.
由于稀缺性，每个社会都必须回答三个基本问题。应该生产什么商品和服务？如何生产，使用哪些要素组合？为谁生产——也就是谁来消费这些产品？不同的经济体制（市场、命令、混合）对这些问题给出不同的答案。
11. Specialisation and Division of Labour | 专业化与劳动分工
Specialisation occurs when workers, firms, or countries concentrate on a narrow range of tasks or products. Division of labour breaks production into small, repeated stages. This can raise productivity (output per worker per hour) but may also make work boring. Industrial efficiency depends on this principle.
专业化是指工人、企业或国家集中于某一狭窄的任务或产品领域。劳动分工将生产分解成小而重复的步骤。这可以提高生产率（每小时每个工人的产出），但也可能使工作变得枯燥。工业效率依赖于这一原理。
Productivity = Total Output ÷ Number of Workers (or hours)
生产率 = 总产出 ÷ 工人数量（或工时）
12. Money: Functions and Characteristics | 货币：功能与特征
Money serves as a medium of exchange, a store of value, a unit of account, and a standard for deferred payment. Good money must be acceptable, portable, durable, divisible, uniform, and limited in supply. These are key concepts when studying the role of financial systems in the economy.
货币充当交换媒介、价值储藏、记账单位以及延期支付的标准。好的货币必须具备可接受性、便携性、耐久性、可分性、同质性和供给有限性。在学习金融体系在经济中的作用时，这些概念至关重要。
Published by TutorHao | Economics Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
或截图后用「扫一扫 → 相册」选择本图