📚 Year 7 Edexcel Economics: Quick Formula Handbook | Year 7 Edexcel 经济:公式定理速查手册
Welcome to your go-to reference for the key formulas and principles in Year 7 Edexcel Economics. This handbook breaks down the essential maths behind basic economic decisions, from scarcity and opportunity cost to demand, supply, and budgeting. Each section provides a clear definition and the formula you need to remember, helping you build a strong foundation for further study.
欢迎使用 Year 7 Edexcel 经济学关键公式与定理速查手册。本手册将基础经济学决策背后的重要数学概念逐一拆解,涵盖稀缺性、机会成本、需求与供给以及预算等主题。每个小节都提供清晰的定义和你需要记住的公式,帮助你为未来的学习打下扎实的基础。
1. Scarcity and Choice | 稀缺性与选择
Scarcity means we have unlimited wants but limited resources. Because of scarcity, every choice involves giving up something else. This is the fundamental problem studied in economics.
稀缺性意味着我们拥有无限的欲望但资源有限。由于稀缺性的存在,每一个选择都意味着放弃其他东西。这是经济学研究的基本问题。
Scarcity Principle: Resources < Wants → Choice must be made
稀缺原理:资源 < 欲望 → 必须做出选择
Economists call these limited resources ‘factors of production’: land, labour, capital, and entrepreneurship.
经济学家将这些有限的资源称为“生产要素”:土地、劳动力、资本和企业家才能。
2. Opportunity Cost Formula | 机会成本公式
Opportunity cost is the value of the next best alternative you give up when you make a choice. It helps you understand the true cost of a decision.
机会成本是你做出一项选择时所放弃的次优选择的价值。它帮助你理解决策的真实成本。
Opportunity Cost = Value of Next Best Alternative Foregone
机会成本 = 所放弃的次优选择的价值
For example, if you spend £10 on a book instead of a cinema ticket, the opportunity cost is the enjoyment you would have gained from watching the film.
例如,如果你花 10 英镑买了一本书而不是电影票,那么机会成本就是你从看电影中本可获得的享受。
3. Demand and Supply Basics | 需求与供给基础
The Law of Demand states that, ceteris paribus (all else being equal), as the price of a good increases, the quantity demanded decreases, and vice versa.
需求定律指出,在其他条件不变的情况下,一种商品的价格上升,需求量就会减少,反之亦然。
Law of Demand: Price ↑ → Quantity Demanded ↓ (and Price ↓ → Qd ↑)
需求定律:价格 ↑ → 需求量 ↓(价格 ↓ → 需求量 ↑)
The Law of Supply states that as the price of a good increases, the quantity supplied increases, because producers are more willing to sell at higher prices.
供给定律指出,一种商品的价格上升,供给量就会增加,因为生产商更愿意以更高的价格出售。
Law of Supply: Price ↑ → Quantity Supplied ↑
供给定律:价格 ↑ → 供给量 ↑
4. Equilibrium Price | 均衡价格
The market is in equilibrium when the quantity demanded equals the quantity supplied. This point gives the equilibrium price and quantity.
当需求量等于供给量时,市场达到均衡。这一点给出了均衡价格和均衡数量。
Market Equilibrium: Qd = Qs
市场均衡:需求量 = 供给量
If price is set above equilibrium, there is excess supply (surplus). If price is below equilibrium, there is excess demand (shortage).
如果价格高于均衡水平,就会出现超额供给(盈余)。如果价格低于均衡水平,就会出现超额需求(短缺)。
5. Price Elasticity of Demand (Simple) | 需求价格弹性(简版)
Price elasticity of demand (PED) measures how much the quantity demanded responds to a change in price. We use a simple version suitable for Year 7.
需求价格弹性(PED)衡量需求量对价格变化的反应程度。这里使用适合七年级的简化版本。
PED = Percentage Change in Quantity Demanded ÷ Percentage Change in Price
需求价格弹性 = 需求量变动百分比 ÷ 价格变动百分比
- If PED > 1, demand is elastic: quantity changes by a bigger percentage than price.
- If PED < 1, demand is inelastic: quantity changes by a smaller percentage than price.
- 若 PED > 1,需求富有弹性:需求量变动百分比大于价格变动百分比。
- 若 PED < 1,需求缺乏弹性:需求量变动百分比小于价格变动百分比。
You can calculate percentage change as: (New – Old) ÷ Old × 100.
你可以这样计算百分比变化:(新值 – 旧值)÷ 旧值 × 100。
6. Cost-Benefit Analysis | 成本效益分析
Cost-benefit analysis is a way to decide whether a choice is worth making by comparing the total expected costs with the total expected benefits.
成本效益分析是一种通过比较总预期成本与总预期收益来判断一项选择是否值得的方法。
Net Benefit = Total Benefits – Total Costs
净收益 = 总收益 – 总成本
If the net benefit is positive, the decision is considered worth taking. This concept is used by individuals, businesses, and governments.
如果净收益为正,该决策就被认为是值得的。个人、企业和政府都会使用这一概念。
7. Budget Line / Budget Constraint | 预算线/预算约束
A budget line shows all the combinations of two goods or services that a consumer can afford given their income and the prices of the goods.
预算线表示在消费者收入和商品价格既定的条件下,他能够负担得起的两种商品或服务的所有组合。
Budget Equation: Income = (P₁ × Q₁) + (P₂ × Q₂)
预算方程:收入 = (商品1价格 × 商品1数量) + (商品2价格 × 商品2数量)
Here, P₁ is the price of good 1, Q₁ is the quantity of good 1. Any point inside the budget line is affordable; points outside are not.
其中 P₁ 是商品 1 的价格,Q₁ 是商品 1 的数量。预算线以内的任何一点都是可以负担的;线外的点则无法负担。
8. Simple Interest Formula | 单利公式
When you save money in a bank account, you may earn simple interest. This is a fixed percentage of the original amount (the principal) paid each year.
当你将钱存入银行账户时,你可能会获得单利。单利是按原始本金固定百分比每年支付的利息。
Simple Interest (I) = P × r × t
单利(I)= 本金 × 年利率 × 年数
P is the principal (original sum), r is the annual interest rate (as a decimal), and t is the time in years. For example, £200 at 5% for 3 years: I = 200 × 0.05 × 3 = £30.
P 是本金,r 是年利率(以小数表示),t 是年限。例如,200 英镑以 5% 的利率存 3 年:I = 200 × 0.05 × 3 = 30 英镑。
9. Profit and Loss | 利润与亏损
Businesses aim to make a profit. Profit is the difference between the money received from selling goods or services (revenue) and the costs of production.
企业以营利为目标。利润是销售商品或服务所得(收入)与生产成本之间的差额。
Profit = Total Revenue – Total Costs
利润 = 总收入 – 总成本
If Total Revenue > Total Costs, the firm makes a profit. If Total Revenue < Total Costs, it makes a loss. Total Revenue = Price × Quantity Sold.
如果总收入 > 总成本,企业盈利。如果总收入 < 总成本,企业亏损。总收入 = 价格 × 销售数量。
10. Exchange Rates Basics | 汇率基础
An exchange rate tells you how much of one currency you can get in exchange for another. They are essential for international trade and travel.
汇率告诉你一种货币可以兑换多少另一种货币。它对国际贸易和旅行至关重要。
1 Unit of Currency A = X Units of Currency B
1 单位 A 货币 = X 单位 B 货币
For example, if £1 = $1.25, then to convert £100 into dollars: 100 × 1.25 = $125. To convert $50 into pounds: 50 ÷ 1.25 = £40.
例如,如果 1 英镑 = 1.25 美元,那么将 100 英镑兑换成美元:100 × 1.25 = 125 美元。将 50 美元兑换成英镑:50 ÷ 1.25 = 40 英镑。
11. Inflation Basics | 通货膨胀基础
Inflation is the general increase in prices over time, which reduces the purchasing power of money. A small, stable inflation rate is normal in most economies.
通货膨胀是指物价总水平在一段时间内持续上涨,从而削弱了货币的购买力。在大多数经济体中,温和稳定的通货膨胀率是正常的。
Inflation Rate = [(New CPI – Old CPI) ÷ Old CPI] × 100
通货膨胀率 = [(新消费者价格指数 – 旧消费者价格指数)÷ 旧消费者价格指数] × 100
CPI stands for Consumer Price Index, a basket of goods that represents what an average household buys.
CPI 代表消费者价格指数,它是一篮子能够代表普通家庭所购商品的物品组合。
12. GDP and Economic Growth | 国内生产总值与经济增长
Gross Domestic Product (GDP) is the total value of all final goods and services produced within a country in a given year. It is the main measure of an economy’s size.
国内生产总值(GDP)是指一个国家在一年内生产的所有最终商品和服务的总价值。它是衡量经济规模的主要指标。
GDP = Sum of (Price × Quantity) for all final goods and services
GDP = 所有最终商品和服务的(价格 × 数量)之和
Economic growth is the percentage increase in real GDP from one year to the next. It shows how much more an economy produces compared to the year before.
经济增长是指实际 GDP 从一个年度到下一个年度的百分比增长。它表明一个经济体与上一年相比多生产了多少。
Economic Growth Rate = [(GDP₂ – GDP₁) ÷ GDP₁] × 100
经济增长率 = [(GDP₂ – GDP₁)÷ GDP₁] × 100
Published by TutorHao | Economics Revision Series | aleveler.com
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