📚 Year 7 CCEA Economics: Formula & Theorem Quick Reference Handbook | 七年级 CCEA 经济：公式定理速查手册
Welcome to your go-to revision guide for Year 7 CCEA Economics. This handbook pulls together all the essential formulas, laws and key terms you need to understand how people make choices about money, resources and trade. From the basic economic problem to calculating profit and interest, every rule is explained simply so you can revise at your own pace.
欢迎使用这份七年级 CCEA 经济学的速查手册。这里汇集了你需要掌握的所有核心公式、定律和关键术语，帮助你理解人们如何围绕金钱、资源和贸易做出选择。从基本经济问题到计算利润和利息，每一条规则都用通俗易懂的方式解释，让你可以按照自己的节奏复习。
1. The Basic Economic Problem: Scarcity | 基本经济问题：稀缺性
Scarcity means that there are never enough resources to satisfy everyone’s unlimited wants. This is the fundamental problem in economics because it forces individuals, businesses and governments to make choices about how to use limited resources like time, money and raw materials.
稀缺性意味着永远没有足够的资源来满足每个人无限的欲望。这是经济学中最根本的问题，因为它迫使个人、企业和政府在时间、金钱和原材料等有限资源的使用上做出选择。
- Resources are limited, but human wants are endless.
- 资源有限，但人的欲望是无穷的。
- Because of scarcity, we must decide what to produce, how to produce it and for whom to produce it.
- 由于稀缺性，我们必须决定生产什么、如何生产以及为谁生产。
2. Opportunity Cost Formula | 机会成本公式
Opportunity cost is the value of the next best alternative that you give up when making a choice. It is not always measured in money – it can be time, enjoyment or another benefit you have to sacrifice.
机会成本是指在做选择时，你放弃的次优选择的价值。它并不总是用金钱来衡量——它可以是你必须牺牲的时间、乐趣或其他收益。
Opportunity Cost = Value of Next Best Alternative Forgone
机会成本 = 放弃的次优选择的价值
If you decide to spend one hour studying economics instead of playing video games, the opportunity cost is the enjoyment you would have gained from the game.
如果你决定花一个小时学习经济学而不是玩电子游戏，那么机会成本就是你原本能从游戏中获得的乐趣。
3. Needs and Wants | 需要与欲望
Needs are essential items for survival, such as food, water, shelter and clothing. Wants are things that make life more comfortable or enjoyable but are not necessary for survival, like a new smartphone or a cinema ticket.
需要是生存所必需的物品，例如食物、水、住所和衣服。欲望是让生活更舒适或更愉快的东西，但对生存来说并非必不可少，比如一部新智能手机或一张电影票。
- Needs are limited; wants are unlimited.
- 需要是有限的；欲望是无限的。
- Scarcity forces us to satisfy needs before most wants.
- 稀缺性迫使我们在满足大多数欲望之前先满足需要。
4. Factors of Production | 生产要素
To produce goods and services, four types of resources are needed. These are known as the factors of production: land (natural resources), labour (human effort), capital (man-made tools and machinery) and enterprise (the ability to bring the other factors together to start a business).
要生产商品和服务，需要四种资源，即生产要素：土地（自然资源）、劳动力（人力）、资本（人造工具和机器）和企业家才能（将其他要素结合起来创业的能力）。
- Land earns rent.
- 土地赚取租金。
- Labour earns wages.
- 劳动力赚取工资。
- Capital earns interest.
- 资本赚取利息。
- Enterprise earns profit.
- 企业家才能赚取利润。
5. The Law of Demand | 需求定律
The law of demand states that, all other things being equal, as the price of a good or service rises, the quantity demanded by consumers falls. Conversely, when the price falls, the quantity demanded increases.
需求定律指出，在其他条件不变的情况下，当商品或服务的价格上涨时，消费者对该商品的需求量下降。相反，当价格下跌时，需求量增加。
Price ↑ → Quantity Demanded ↓
价格上涨 → 需求量下降
This inverse relationship is the reason why sale discounts attract more buyers.
这种反向关系是打折促销能吸引更多购买者的原因。
6. The Law of Supply | 供给定律
The law of supply explains that, all other things being equal, as the price of a good or service rises, the quantity supplied by producers increases. A higher price often motivates firms to produce more because they can earn greater revenue.
供给定律说明，在其他条件不变的情况下，当商品或服务的价格上涨时，生产者的供给量增加。较高的价格通常会激励企业生产更多，因为他们可以获得更高的收入。
Price ↑ → Quantity Supplied ↑
价格上涨 → 供给量增加
7. Total Revenue Formula | 总收入公式
Total revenue is the money a business receives from selling its goods or services. It is a key number used to work out whether a firm is covering its costs.
总收入是企业通过销售其商品或服务获得的资金。它是用来计算企业是否能够收回成本的关键数据。
Total Revenue (TR) = Price per unit (P) × Quantity sold (Q)
总收入 = 单位价格 × 销售数量
If a bookshop sells 50 books at £8 each, TR = £8 × 50 = £400.
如果一家书店以每本8英镑的价格售出50本书，总收入 = 8 × 50 = 400 英镑。
8. Total Cost and Profit Calculation | 总成本与利润计算
Total cost is the full expense a business incurs when producing goods or services. Profit is the reward for taking risks and is calculated by subtracting total cost from total revenue.
总成本是企业在生产商品或服务时发生的全部支出。利润是对承担风险的回报，通过从总收入中减去总成本来计算。
Total Cost (TC) = all expenses (e.g. raw materials, wages, rent)
总成本 = 所有开支（如原材料、工资、租金）
Profit = Total Revenue – Total Cost
利润 = 总收入 – 总成本
If TR = £400 and TC = £250, profit = £400 – £250 = £150.
如果总收入为400英镑，总成本为250英镑，利润 = 400 – 250 = 150 英镑。
9. Simple Interest Formula | 单利公式
When you save money in a bank or borrow money, interest is the extra amount paid or earned. Simple interest is calculated only on the original amount (the principal) for each period.
当你在银行存钱或借钱时，利息是支付或赚取的额外金额。单利仅按原始金额（本金）在每一期计算。
Simple Interest (I) = Principal (P) × Rate (R) × Time (T)
单利 = 本金 × 年利率 × 时间（年）
If you save £200 at an interest rate of 5% per year for 3 years, I = 200 × 0.05 × 3 = £30.
如果你以每年5%的利率存入200英镑，存期3年，利息 = 200 × 0.05 × 3 = 30 英镑。
10. Budget Balance | 预算平衡
A budget is a plan for how to spend and save money. The budget balance helps you see whether you are living within your means or overspending.
预算是一个关于如何支出和储蓄的计划。预算平衡帮助你了解自己是否量入为出，还是超支了。
Budget Balance = Total Income – Total Expenses
预算平衡 = 总收入 – 总支出
- A positive balance means a surplus (you can save more).
- 正数表示盈余（你可以存更多钱）。
- A negative balance means a deficit (you are spending more than you earn).
- 负数表示赤字（你的支出超过了收入）。
11. Exchange Rate Conversion | 汇率换算
Exchange rates show how much one currency is worth in terms of another. This is essential when travelling abroad or buying goods from another country.
汇率显示一种货币兑换另一种货币的价值。这在出国旅行或从其他国家购买商品时至关重要。
Amount in foreign currency = Amount in home currency × Exchange rate
外币金额 = 本币金额 × 汇率
If £1 = 1.15 euros and you exchange £100, you receive 100 × 1.15 = 115 euros.
如果1英镑 = 1.15欧元，你兑换100英镑，就能得到100 × 1.15 = 115欧元。
12. Average Cost and Efficiency | 平均成本与效率
Average cost tells us how much it costs to produce one unit of a good on average. Lower average costs often mean a business is becoming more efficient, perhaps by producing in larger batches or using better technology.
平均成本告诉我们平均生产一单位商品的成本是多少。平均成本降低通常意味着企业变得更有效率，这可能是通过大批量生产或使用更好的技术实现的。
Average Cost (AC) = Total Cost (TC) ÷ Quantity produced (Q)
平均成本 = 总成本 ÷ 生产数量
If a baker spends £60 to make 30 loaves of bread, the average cost per loaf is £60 ÷ 30 = £2.
如果一个面包师花费60英镑制作了30条面包，每条面包的平均成本是60 ÷ 30 = 2英镑。
Published by TutorHao | Economics Revision Series | aleveler.com
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