📚 GCSE Edexcel Economics: Calculation Practice Drill | GCSE Edexcel 经济：计算题专项训练
This article provides a focused drill on all the essential calculations you need to master for the GCSE Edexcel Economics exam. From percentage changes to elasticities, costs, revenues, break-even, and macroeconomic indicators, each section offers clear formulas, step-by-step examples, and paired English and Chinese explanations to support bilingual learners.
本文专项训练GCSE Edexcel经济考试中所有必会计算题型。从百分比变化到弹性、成本、收益、盈亏平衡及宏观经济指标，每节提供清晰公式、分步示例，并配有英中双语解释，助力双语学习者掌握核心技能。
1. Introduction to Calculations in GCSE Economics | 经济计算题简介
Calculations are a core skill in GCSE Economics. They appear in multiple-choice, short-answer and data-response questions. You must be able to compute and interpret percentage changes, elasticities, costs, revenues, profits, and economic indicators.
计算是GCSE经济学的核心技能，出现在选择题、简答题和数据分析题中。你必须能够计算并解释百分比变化、弹性、成本、收益、利润以及经济指标。
This drill covers all syllabus requirements, with formulas presented in a consistent format and applied to realistic scenarios.
本训练涵盖所有教学大纲要求，公式以统一格式呈现并应用于真实场景。
2. Percentage Changes | 百分比变化
Percentage change is the foundation of elasticity and many economic comparisons. The formula is:
百分比变化是弹性和许多经济比较的基础。公式为：
%Δ = (New Value − Old Value) ÷ Old Value × 100
For example, if the price of a coffee rises from £2.50 to £3.00, the percentage change in price is ((3.00 – 2.50) ÷ 2.50) × 100 = 20%.
例如，一杯咖啡的价格从2.50英镑涨到3.00英镑，价格变化的百分比为((3.00 – 2.50) ÷ 2.50) × 100 = 20%。
Always remember that a negative result indicates a decrease. When calculating percentage changes for elasticity, we often use the absolute value for PED but keep the sign for YED and PES.
记住，负值表示下降。在计算弹性时，PED通常取绝对值，而YED和PES保留符号。
3. Price Elasticity of Demand (PED) | 需求价格弹性
PED measures the responsiveness of quantity demanded to a change in price. Formula:
PED衡量需求量对价格变动的反应程度。公式：
PED = %ΔQd ÷ %ΔP
Since price and quantity demanded are inversely related, PED is usually negative, but we often ignore the minus sign and use the absolute value.
由于价格与需求量呈反向关系，PED通常为负数，但我们常忽略负号，使用绝对值。
If a 10% rise in ticket prices leads to a 5% fall in quantity demanded, PED = –5% ÷ 10% = –0.5. The absolute value is 0.5, indicating inelastic demand.
如果票价上涨10%，需求量下降5%，则PED = –5% ÷ 10% = –0.5。绝对值为0.5，表明需求缺乏弹性。
Interpretations: |PED| > 1 elastic; |PED| = 1 unit elastic; |PED| < 1 inelastic. The steeper the demand curve, the more inelastic the demand at that point.
解读：|PED| > 1 富有弹性；|PED| = 1 单位弹性；|PED| < 1 缺乏弹性。需求曲线越陡峭，在该点的需求越缺乏弹性。
Exam tip: When calculating PED from two price-quantity points, GCSE often uses simple percentage change unless a midpoint method is instructed.
考试提示：如果从两组价格—数量点计算，GCSE通常使用简单百分比变化公式，除非题目要求弧弹性法。
4. Income Elasticity of Demand (YED) | 收入需求弹性
YED measures the responsiveness of demand to changes in income. Formula:
YED衡量需求对收入变动的反应程度。公式：
YED = %ΔQd ÷ %ΔY
Unlike PED, the sign of YED is crucial. A positive YED indicates a normal good; a negative YED indicates an inferior good.
与PED不同，YED的正负号非常重要。YED为正表示正常品；YED为负表示低档品。
If income rises by 4% and demand for organic vegetables rises by 8%, YED = 8% ÷ 4% = +2. This is a luxury normal good.
如果收入增长4%，有机蔬菜的需求增长8%，YED = 8% ÷ 4% = +2。这是一种奢侈品（高收入弹性正常品）。
If demand for supermarket own-brand beans falls by 3% when income rises by 5%, YED = –3% ÷ 5% = –0.6, an inferior good.
如果收入增长5%时，超市自有品牌豆类的需求下降3%，YED = –3% ÷ 5% = –0.6，低档品。
You may be asked to interpret the coefficient or predict demand changes.
你可能需要解释弹性系数或预测需求变化。
5. Price Elasticity of Supply (PES) | 供给价格弹性
PES measures the responsiveness of quantity supplied to a change in price. Formula:
PES衡量供给量对价格变动的反应程度。公式：
PES = %ΔQs ÷ %ΔP
PES is usually positive because supply curves slope upward. Values between 0 and 1 indicate inelastic supply; greater than 1 is elastic supply.
PES通常为正，因为供给曲线向上倾斜。0到1之间表示供给缺乏弹性；大于1表示供给富有弹性。
Factors like production time, spare capacity, and storage ability affect PES. Calculations are straightforward percentage changes.
生产时间、闲置产能和储存能力等因素影响PES。计算直接使用百分比变化。
Example: If a 15% rise in the price of wheat causes a 10% increase in quantity supplied, PES = 10% ÷ 15% = 0.67 (inelastic supply).
示例：如果小麦价格上涨15%，供给量增加10%，PES = 10% ÷ 15% = 0.67（供给缺乏弹性）。
6. Total Revenue and the Relationship with PED | 总收益及其与需求价格弹性的关系
Total revenue (TR) is the money a firm receives from sales. Formula:
总收益（TR）是企业从销售中获得的收入。公式：
TR = Price × Quantity Sold
The link between PED and TR is a common exam question. If demand is elastic (|PED| > 1), a price cut raises total revenue because the percentage increase in quantity demanded is larger than the percentage fall in price.
PED与TR的关系是常见考题。如果需求富有弹性（|PED| > 1），降价会使总收益增加，因为需求量增加的百分比大于价格下降的百分比。
If demand is inelastic (|PED| < 1), a price rise increases total revenue because quantity demanded falls by a smaller percentage.
如果需求缺乏弹性（|PED| < 1），涨价会增加总收益，因为需求量下降的百分比较小。
Calculate TR before and after the price change to verify. Example: Original price £5, quantity 200 → TR = £1000. New price £4, quantity 300 → TR = £1200. TR increased, so demand is elastic.
计算价格变动前后的TR以验证。例如：原价5英镑，销量200 → TR = 1000英镑。新价4英镑，销量300 → TR = 1200英镑。TR增加，说明需求富有弹性。
7. Costs of Production: Total, Fixed, Variable and Average Costs | 生产成本：总成本、固定成本、可变成本与平均成本
Total cost (TC) = Total fixed cost (TFC) + Total variable cost (TVC). Fixed costs do not vary with output (e.g., rent); variable costs change with output (e.g., raw materials).
总成本（TC）= 总固定成本（TFC）+ 总可变成本（TVC）。固定成本不随产量变化（如租金）；可变成本随产量变化（如原材料）。
Average cost (ATC) = TC ÷ Output. Also called unit cost. You may need to calculate average fixed cost (AFC) = TFC ÷ Q and average variable cost (AVC) = TVC ÷ Q.
平均成本（ATC）= TC ÷ 产量。也称为单位成本。你可能需要计算平均固定成本（AFC）= TFC ÷ Q，平均可变成本（AVC）= TVC ÷ Q。
Example: A baker’s fixed costs are £500 per week. Variable cost is £2 per loaf. If they produce 400 loaves, TC = 500 + (2 × 400) = £1300. ATC = 1300 ÷ 400 = £3.25.
示例：面包店每周固定成本500英镑，每个面包可变成本2英镑。如果生产400个面包，TC = 500 + (2 × 400) = 1300英镑。ATC = 1300 ÷ 400 = 3.25英镑。
Diagrams often require labeling average and marginal costs, but calculations focus on these formulas.
图表通常需要标注平均成本和边际成本，但计算题主要围绕这些公式。
8. Revenue and Profit Calculations | 收入与利润计算
Profit is the difference between total revenue and total costs. Formula:
利润是总收益与总成本的差额。公式：
Profit = TR − TC
You can also calculate profit per unit: Profit per unit = Selling price − ATC. This is useful for evaluating a firm’s performance.
也可以计算单位利润：单位利润 = 售价 − 平均总成本。这有助于评价企业绩效。
Example: A firm sells 5000 units at £20 each. TR = £100,000. TC = £80,000. Profit = £20,000. Profit per unit = £20 − (£80,000 ÷ 5000) = £20 − £16 = £4.
示例：企业以每件20英镑售出5000件，TR = 100,000英镑，TC = 80,000英镑。利润 = 20,000英镑。单位利润 = 20 − (80,000 ÷ 5000) = 20 − 16 = 4英镑。
For GCSE Edexcel, focus on total profit and profit per unit.
GCSE Edexcel 主要关注总利润和单位利润。
9. Break-even Analysis | 盈亏平衡分析
Break-even is the level of output where TR = TC, so profit is zero. The break-even point can be found using a formula or a chart.
盈亏平衡点是指总收益等于总成本、利润为零的
Published by TutorHao | GCSE Economics Revision Series | aleveler.com
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