GCSE Economics: Formula Summary Handbook | GCSE 经济：公式汇总手册

📚 GCSE Economics: Formula Summary Handbook | GCSE 经济：公式汇总手册

Mastering key economic formulas is essential for GCSE Economics success. This handbook compiles all the crucial equations and calculations you need to analyse markets, firms, and the macroeconomy. From elasticities to costs and from productivity to inflation, each formula is presented with clear definitions and worked examples. Use this guide as your quick-reference companion when revising for your exams.

掌握关键经济公式对于 GCSE 经济的成功至关重要。本手册汇集了分析市场、企业和宏观经济所需的所有重要方程和计算。从弹性到成本，从生产率到通货膨胀，每个公式都有清晰的定义和示例。在备考复习时，将本指南作为快速参考的好帮手。

1. Price Elasticity of Demand (PED) | 需求的价格弹性

Price elasticity of demand (PED) measures the responsiveness of quantity demanded to a change in price. It is calculated using the formula:

需求的价格弹性（PED）衡量需求量对价格变化的反应程度。其计算公式为：

PED = %Δ in Quantity Demanded / %Δ in Price

A step-by-step method: first calculate the percentage change in quantity demanded: ((Q₂ − Q₁) / Q₁) × 100 ; then calculate the percentage change in price: ((P₂ − P₁) / P₁) × 100. Finally, divide the first result by the second.

分步计算方法：首先计算需求量变化的百分比：((Q₂ − Q₁) / Q₁) × 100 ；然后计算价格变化的百分比：((P₂ − P₁) / P₁) × 100。最后，用第一个结果除以第二个结果。

If PED > 1, demand is price elastic; if PED < 1, demand is price inelastic; if PED = 1, demand is unit elastic.

若 PED > 1，需求富有价格弹性；若 PED < 1，需求缺乏价格弹性；若 PED = 1，需求为单位弹性。

Example: A price rise from £5 to £6 causes the quantity demanded to fall from 100 units to 80 units. %ΔQd = ((80 − 100)/100) × 100 = −20% ; %ΔP = ((6 − 5)/5) × 100 = 20% ; PED = −20% / 20% = −1. Ignoring the negative sign, the magnitude is 1 → unit elastic.

示例：价格从 5 英镑升至 6 英镑，导致需求量从 100 单位降至 80 单位。%ΔQd = ((80 − 100)/100) × 100 = −20% ；%ΔP = ((6 − 5)/5) × 100 = 20% ；PED = −20% / 20% = −1。忽略负号，大小为 1 → 单位弹性。

---

2. Income Elasticity of Demand (YED) | 需求的收入弹性

Income elasticity of demand (YED) measures how quantity demanded responds to a change in consumers’ income.

需求的收入弹性（YED）衡量需求量对消费者收入变化的反应程度。

YED = %Δ in Quantity Demanded / %Δ in Income

Calculate percentage changes in the same way as PED. A positive YED indicates a normal good; a negative YED indicates an inferior good.

百分比变化的计算方法与 PED 相同。YED 为正表示正常商品；YED 为负表示劣等商品。

If YED > 1, the good is luxury; if 0 < YED < 1, it is a necessity.

若 YED > 1，该商品为奢侈品；若 0 < YED < 1，则为必需品。

Example: Incomes rise by 5% and demand for organic food increases by 8%. YED = 8% / 5% = +1.6. This indicates a luxury normal good.

示例：收入增长 5%，有机食品需求增长 8%。YED = 8% / 5% = +1.6。这表明它是奢侈正常商品。

---

3. Cross Elasticity of Demand (XED) | 需求的交叉弹性

Cross elasticity of demand (XED) measures the responsiveness of demand for one good (Good A) to a change in the price of another good (Good B).

需求的交叉弹性（XED）衡量一种商品（商品 A）的需求对另一种商品（商品 B）价格变化的反应程度。

XED = %Δ in Quantity Demanded of Good A / %Δ in Price of Good B

A positive XED indicates substitutes; a negative XED indicates complements. The larger the magnitude, the stronger the relationship.

XED 为正表示替代品；XED 为负表示互补品。数值越大，关系越强。

Example: The price of tea rises by 10% and demand for coffee increases by 15%. XED = +15% / +10% = +1.5. Tea and coffee are substitutes.

示例：茶叶价格上涨 10%，咖啡需求增加 15%。XED = +15% / +10% = +1.5。茶和咖啡是替代品。

---

4. Price Elasticity of Supply (PES) | 供给的价格弹性

Price elasticity of supply (PES) measures the responsiveness of quantity supplied to a change in price.

供给的价格弹性（PES）衡量供给量对价格变化的反应程度。

PES = %Δ in Quantity Supplied / %Δ in Price

If PES > 1, supply is price elastic; if PES < 1, supply is price inelastic; if PES = 1, unit elastic.

若 PES > 1，供给富有弹性；若 PES < 1，供给缺乏弹性；若 PES = 1，为单位弹性。

Supply is more elastic when firms have spare capacity, stocks, or a short production time.

当企业拥有闲置产能、库存或生产时间短时，供给弹性较大。

Example: Price increases from £10 to £12 (20% rise) and quantity supplied expands from 200 to 260 (30% rise). PES = 30% / 20% = 1.5 → elastic supply.

示例：价格从 10 英镑升至 12 英镑（上涨 20%），供给量从 200 增至 260（上升 30%）。PES = 30% / 20% = 1.5 → 供给富有弹性。

---

5. Total, Average and Marginal Costs | 总成本、平均成本与边际成本

Understanding cost structures is crucial for analysing a firm’s efficiency and pricing decisions.

理解成本结构对于分析企业的效率和定价决策至关重要。

Total Cost (TC) = Total Fixed Cost (TFC) + Total Variable Cost (TVC)

总成本 (TC) = 总固定成本 (TFC) + 总可变成本 (TVC)

TC = TFC + TVC

Average Total Cost (ATC) = Total Cost / Quantity of output (Q)

平均总成本 (ATC) = 总成本 / 产量 (Q)

ATC = TC ÷ Q

Average Fixed Cost (AFC) = TFC / Q ; Average Variable Cost (AVC) = TVC / Q

平均固定成本 (AFC) = TFC / Q ；平均可变成本 (AVC) = TVC / Q

Marginal Cost (MC) is the additional cost of producing one more unit: MC = Change in Total Cost / Change in Quantity.

边际成本 (MC) 是再多生产一单位产品所增加的成本：MC = 总成本变动量 / 产量变动量。

MC = ΔTC / ΔQ

Example: If total cost rises from £2000 to £2300 when output increases from 100 to 120 units, then MC = (2300 − 2000) / (120 − 100) = 300 / 20 = £15.

示例：当产量从 100 单位增加到 120 单位时，总成本从 2000 英镑升至 2300 英镑，则 MC = (2300 − 2000) / (120 − 100) = 300 / 20 = 15 英镑。

---

6. Revenue and Profit | 收益与利润

Revenue is the income a firm receives from selling its goods or services.

收益是企业销售商品或服务所获得的收入。

Total Revenue (TR) = Price × Quantity sold

总收入 (TR) = 价格 × 销售量

TR = P × Q

Average Revenue (AR) = TR / Q = Price (in perfect competition, AR equals the demand curve)

平均收入 (AR) = TR / Q = 价格（在完全竞争市场中，AR 等于需求曲线）

Marginal Revenue (MR) = Change in Total Revenue / Change in Quantity sold

边际收入 (MR) = 总收入变动量 / 销售量变动量

MR = ΔTR / ΔQ

Profit = Total Revenue − Total Cost

利润 =

Published by TutorHao | GCSE Economics Revision Series | aleveler.com

更多咨询请联系16621398022（同微信）