📚 Year 7 WJEC Business: Formula & Theorem Quick Reference | 七年级 WJEC 商务：公式定理速查手册
This handbook brings together all the essential formulas and economic principles you need to know for Year 7 WJEC Business Studies. Each topic is explained clearly with a worked example, so you can apply the right calculation in exams and class tasks. Keep this guide handy whenever you revise costs, revenues, profit and the key decision-making tools used by small businesses.
这本手册汇总了 WJEC 七年级商务课程中必须掌握的核心公式和经济原理。每个主题都配合清晰的示例进行解释，帮助你在考试和课堂任务中准确运用。无论是成本、收入、利润还是小企业常用的决策工具，你都可以随时查阅这本速查手册。
1. Revenue Formula | 收入公式
Revenue, sometimes called turnover or sales revenue, is the total amount of money a business receives from selling its products or services. It is the starting point for measuring whether a business is generating enough cash to cover its costs.
收入，有时也叫营业额或销售收入，是企业通过销售产品或服务获得的总金额。它是衡量企业能否赚到足够资金来覆盖成本的第一步。
To calculate total revenue, you multiply the selling price of one unit by the quantity sold. This simple formula helps a business set sales targets and forecast future income.
要计算总收入，需要用单位售价乘以销售数量。这个简单的公式有助于企业设定销售目标和预测未来收入。
Revenue = Selling Price per Unit × Quantity Sold
Example: A street food stall sells burgers at £5 each. On a busy Saturday it sells 200 burgers. Total revenue = £5 × 200 = £1,000.
示例：一个街边小吃摊每个汉堡售价5英镑，周六生意火爆售出200个。总收入 = 5英镑 × 200 = 1000英镑。
Reminder: Revenue is not the same as profit. You must subtract costs before you know whether the business actually made money.
提示：收入不等于利润。只有减掉成本之后，才能知道企业是否真正赚到了钱。
2. Fixed and Variable Costs | 固定成本与可变成本
Costs are the expenses a business must pay in order to operate. They are divided into two main types: fixed costs and variable costs. Understanding this split is vital for budgeting and for calculating profit.
成本是企业在经营中必须支付的费用，分为两大类：固定成本和可变成本。理解这种分类对于编制预算和计算利润至关重要。
Fixed costs stay the same regardless of how many products the business makes or sells. Examples include rent, insurance and salaries of permanent staff. Even if the business produces nothing, it still has to pay fixed costs.
固定成本无论企业生产或销售多少产品都保持不变。租金、保险和正式员工的工资都属于固定成本。即使企业不生产任何产品，也得支付这些费用。
Variable costs change directly with the level of output or sales. The more you produce, the higher your variable costs become. Raw materials, packaging and hourly wages are typical variable costs.
可变成本直接随着产出或销售量的变化而变化。产量越高，可变成本就越高。原材料、包装费和临时工计时工资是典型的可变成本。
Total Cost = Fixed Costs + Variable Costs
This classification is the foundation for almost every other business calculation you will learn.
这种分类是你将学到的几乎所有其他商业计算的基础。
3. Total Cost Calculation | 总成本计算
Once you have identified your fixed and variable costs, you can work out the total cost of running the business over a given period. This figure tells a business how much it needs to earn just to break even.
确定固定成本和可变成本后，就能算出企业在特定时期内经营所需的总成本。这个数字告诉企业，至少需要赚多少钱才能实现不盈不亏。
The formula adds all fixed costs to the total variable costs. Variable costs are often expressed per unit, so you multiply the variable cost per unit by the number of units produced.
该公式将所有固定成本与总可变成本相加。可变成本通常按单位计算，因此需要用单位可变成本乘以生产的数量。
Total Cost = Fixed Costs + (Variable Cost per Unit × Output)
Example: A bakery pays £800 per month in rent and insurance (fixed costs). Each loaf costs £ our and energy (variable cost per unit). If it bakes 5,000 loaves in a month, total cost = £800 + (£0.40 × 5,000) = £800 + £2,000 = £2,800.
示例：一家面包店每月支付800英镑租金和保险（固定成本）。每条面包需要0.40英镑的面粉和能源（单位可变成本）。如果一个月烤5000条面包，总成本 = 800 + (0.40 × 5000) = 800 + 2000 = 2800英镑。
Knowing total cost helps a business set prices that cover all expenses and leave room for profit.
了解总成本有助于企业制定能够覆盖全部开销并留有利润空间的价格。
4. Profit Formula | 利润公式
Profit is the reward a business receives for taking risks. It is what remains after deducting all costs from total revenue. Without profit, a business cannot survive in the long run.
利润是企业承担风险所获得的回报。它是从总收入中扣除所有成本后剩下的部分。没有利润，企业就无法长期生存。
The profit formula is one of the most fundamental in business studies, and it appears in almost every exam paper. You can also rearrange it to find revenue or total cost if the other two values are known.
利润公式是商务学科最基础的公式之一，几乎每次考试都会出现。如果知道另外两个数值，还可以通过变形公式求出收入或总成本。
Profit = Total Revenue – Total Cost
Example: A craft business sells handmade necklaces. Total revenue for the month is £2,400. Total cost (materials, stall fees, website) is £1,600. Profit = £2,400 – £1,600 = £800.
示例：一家手工艺品企业销售手工项链。当月总收入为2400英镑，总成本（材料、摊位费、网站）为1600英镑。利润 = 2400 – 1600 = 800英镑。
Businesses also talk about gross profit and net profit. At Year 7 level, focus on the basic profit equation and remember that if total cost is greater than total revenue, the business makes a loss.
企业还会用到毛利润和净利润的概念。在七年级阶段，先掌握基本利润公式，并且记住当总成本大于总收入时，企业就会亏损。
5. Profit Margin | 利润率
Profit margin shows how much profit a business makes for every pound of revenue. It is a percentage that makes it easier to compare performance across different periods or between different firms.
利润率显示企业每赚取1英镑收入能获得多少利润。这个百分比便于比较不同时期或不同公司之间的业绩。
A higher profit margin means the business is keeping more of its sales revenue as profit after covering costs. Businesses aim to improve their margin by increasing prices or cutting costs.
较高的利润率意味着企业在覆盖成本之后，能将更多的销售收入保留为利润。企业通过提高价格或削减成本来提高利润率。
Profit Margin (%) = (Profit ÷ Revenue) × 100
Example: Using the craft business from Section 4, profit = £800 and revenue = £2,400. Profit margin = (800 ÷ 2,400) × 100 = 33.3%. This means for every £1 of revenue, the business earns approximately 33p in profit.
示例：沿用第4节的手工艺品企业，利润=800英镑，收入=2400英镑。利润率 = (800 ÷ 2400) × 100 = 33.3%。这意味着每赚取1英镑收入，企业获得约33便士的利润。
Managers watch profit margin closely because rising costs can quickly shrink the percentage, even if sales are growing.
管理者密切监视利润率，因为即使销售增长，上升的成本也会迅速压低这个百分比。
6. Break-even Point | 盈亏平衡点
Break-even is the point where total revenue equals total cost. At this output level, the business makes neither a profit nor a loss. It is a crucial target for new businesses because it tells them the minimum sales needed to survive.
盈亏平衡点是指总收入等于总成本的状态。在这个产出水平上，企业既没有利润也没有亏损。这对新企业来说是一个关键目标，因为它告诉企业至少需要销售多少才能维持生存。
The break-even formula uses fixed costs, the selling price per unit and the variable cost per unit. The difference between selling price and variable cost is called the contribution per unit.
盈亏平衡公式使用固定成本、单位售价和单位可变成本。售价与可变成本的差额称为单位边际贡献。
Break-even Output = Fixed Costs ÷ (Selling Price per Unit – Variable Cost per Unit)
Example: A poster printing business has fixed costs of £300 per month. Each poster sells for £5, and the variable cost of printing one poster (paper, ink) is £2. Contribution per unit = £5 – £2 = £3. Break-even output = £300 ÷ £3 = 100 posters per month.
示例：一家海报打印公司每月固定成本为300英镑。每张海报售价5英镑，印刷一张海报的可变成本（纸张、油墨）为2英镑。单位边际贡献 = 5 – 2 = 3英镑。盈亏平衡产量 = 300 ÷ 3 = 每月100张海报。
The table below shows how revenue and costs change as output grows. You can see the business moves into profit once it passes 100 units.
下表展示了随着产量增长，收入和成本的变化。可以看到，产量一旦超过100个单位，企业就开始盈利。
| Output (posters) | Fixed Costs (£) | Variable Costs (£) | Total Cost (£) | Revenue (£) | Profit/Loss (£) |
|---|---|---|---|---|---|
| 0 | 300 | 0 | 300 | 0 | -300 |
| 50 | 300 | 100 | 400 | 250 | -150 |
| 100 | 300 | 200 | 500 | 500 | 0 |
| 150 | 300 | 300 | 600 | 750 | +150 |
Businesses use break-even analysis when deciding whether to launch a new product or to judge how risky a venture might be.
企业用盈亏平衡分析来决定是否推出新产品，或者判断某个项目可能有多大风险。
7. Cost-Plus Pricing | 加成定价
Cost-plus pricing is a simple method for setting the selling price. A business calculates the total cost of producing one unit and then adds a percentage mark-up to ensure a profit.
加成定价法是一种简单的定价方法。企业先算出生产一个单位的总成本，再加上一定百分比的加成，从而保证获得利润。
This approach is popular because it is straightforward and ensures that every product sold contributes towards covering overheads and generating profit.
这种方法很受欢迎，因为它简单明了，能确保每件售出的产品都能分担企业的一般管理费用并产生利润。
Selling Price = Cost per Unit × (1 + Mark-up %)
ark-up is already expressed as a monetary amount: Selling Price = Cost per Unit + Mark-up.
或者，如果加成已经表示为一个货币金额：售价 = 单位成本 + 加成金额。
Example: A furniture maker builds a chair at a total cost of £40 per unit. The business applies a 50% mark-up. Selling price = £40 × 1.50 = £60. The £20 difference is the mark-up that contributes to profit.
示例：一个家具厂制作一把椅子的单位总成本为40英镑，企业采用50%的加成。售价 = 40 × 1.50 = 60英镑。其中20英镑的差价就是贡献给利润的加成部分。
Reminder: Cost-plus pricing does not consider what customers are willing to pay or what competitors charge, so businesses often combine it with market research.
提示：加成定价法没有考虑顾客愿意付多少钱，也没有考虑竞争对手的定价，因此企业通常还会结合市场调研来使用。
8. Net Cash Flow | 净现金流
Cash flow refers to the movement of money into and out of a business. Net cash flow is the difference between all cash inflows and all cash outflows in a given period. It tells a business whether its bank balance is rising or falling.
现金流是指资金流入和流出企业的运动。净现金流是在特定时期内所有现金流入与所有现金流出的差额。它告诉企业，其银行余额是在增加还是在减少。
A positive net cash flow means the business has more cash coming in than going out, which helps it pay bills on time and invest in growth. A negative net cash flow warns that the business might run out of cash.
正向净现金流意味着企业流入的现金多于流出的现金，这使它能够按时支付账单并投资于增长。负向净现金流则警示企业可能会耗尽现金。
Net Cash Flow = Total Cash Inflows – Total Cash Outflows
Example: A small cafe has cash inflows of £ food sales and a small bank loan. Its cash outflows (wages, stock, rent, utilities) total £8,200. Net cash flow = £9,500 – £8,200 = £1,300 positive.
示例：一家小咖啡店3月份现金流入为9500英镑，来自食品销售和一笔小额银行贷款。现金流出（工资、存货、租金、水电费）总计8200英镑。净现金流 = 9500 – 8200 = +1300英镑。
Businesses prepare cash flow forecasts to predict future cash balances. A profitable business can still fail if it does not manage its cash flow carefully.
企业会编制现金流量预测来预估未来的现金余额。如果现金流管理不善，即使盈利的企业也可能失败。
9. Law of Demand | 需求定律
The law of demand is a key economic theorem that describes how consumers react to changes in price. It states that, all else being equal, when the price of a product rises, the quantity demanded falls; when the price falls, the quantity demanded rises.
需求定律是描述消费者如何对价格变化作出反应的重要经济定理。它认为，在其他条件相同的情况下，当产品价格上升时，需求量会下降；当价格下降时，需求量会上升。
This inverse relationship exists because consumers have limited budgets and usually seek cheaper alternatives when prices increase. It helps businesses predict how sales might change if they alter their prices.
这种反向关系之所以存在，是因为消费者预算有限，而且当价格上涨时通常会寻找更便宜的替代品。这有助于企业预测，如果调整价格，销售量可能会发生怎样的变化。
Although the law of demand is a general rule, some exceptions exist, such as luxury goods that can see higher demand when prices rise because they become status symbols. For your course, focus on the standard relationship.
尽管需求定律是一条通用规则，但也存在例外，比如某些奢侈品价格上升时需求反而增加，因为它们成为地位的象征。在学习阶段，请掌握标准关系。
On a demand curve, this relationship is shown by a downward-sloping line from left to right. The quantity demanded goes on the horizontal axis and price on the vertical axis.
在需求曲线上，这种关系表现为从左向右下方倾斜的线条。需求量标在横轴上，价格标在纵轴上。
10. Budget Variance | 预算差异
A budget is a financial plan that estimates future income and spending. Budget variance measures the difference between the budgeted (planned) figure and the actual figure. It helps managers spot where performance has been better or worse than expected.
预算是一个估算未来收入和支出的财务计划。预算差异衡量的是预算（计划）数字与实际数字之间的差额。它帮助管理者发现哪些方面的表现优于或差于预期。
The formula is simple, but you need to label the result as favourable (F) or adverse (A). A favourable variance means actual results are better for the business's financial position, while an adverse variance means they are worse.
计算公式很简单，但你需要将结果标记为有利差异 (F) 或不利差异 (A)。有利差异意味着实际结果对企业财务状况更有利，不利差异则意味着更不利。
Variance = Actual Figure – Budgeted Figure
For costs, a negative variance (actual cost less than budget) is favourable because the business spent less than planned. For revenue, a positive variance (actual revenue more than budget) is favourable.
对于成本而言，负差异（实际成本低于预算）是有利的，因为企业花费得比计划少。对于收入而言，正差异（实际收入高于预算）是有利的。
Example: A school canteen budgets £2,000 for food supplies in January but actually spends £2,350. Variance = £2,350 – £2,000 = £350 adverse (A). The manager would investigate why spending was higher.
示例：学校食堂预算1月份食品原料支出2000英镑，但实际花费2350英镑。差异 = 2350 – 2000 = 350英镑不利差异 (A)。管理者会调查为什么支出会超预算。
Analysing variances regularly allows a business to control costs and make quick adjustments to keep finances on track.
定期分析差异能让企业控制成本，并迅速作出调整，使财务状况保持在轨道上。
11. Productivity | 生产率
Productivity measures how efficiently a business uses its resources to produce goods or services. It is usually expressed as output per worker or output per machine hour. Higher productivity means lower costs per unit, which can lead to higher profits or lower prices for customers.
生产率衡量企业利用资源生产商品或服务的效率，通常表示为每个工人的产出或每机时的产出。较高的生产率意味着单位成本更低，进而可能带来更高利润或更低售价。
The most common productivity formula at this level is labour productivity. You divide total output by the number of workers (or by the number of hours worked).
在这个学习阶段，最常见的生产率公式是劳动生产率。需要用总产出除以工人数量（或工作小时数）。
Labour Productivity = Total Output ÷ Number of Employees
a week with 25 workers. Labour productivity = 20,000 ÷ 25 = 800 boxes per worker per week.
示例：一家包装工厂在一周内生产了20000个盒子，雇佣了25名工人。劳动生产率 = 20000 ÷ 25 = 每名工人每周800个盒子。
If the factory introduced better machinery and the same workers produced 24,000 boxes, labour productivity would rise to 960 boxes per worker. This would reduce the labour cost per box.
如果工厂引进了更好的机器，同样的工人生产了24000个盒子，那么劳动生产率会上升到每名工人960个。这会降低每个盒子的劳动力成本。
Improving productivity is a constant challenge. Training, technology and staff motivation all play a part.
提高生产率是一个持续的挑战。培训、技术和员工激励都发挥着作用。
12. Market Growth Rate | 市场增长率
Market growth measures how much a market changes in size over a period of time, usually a year. It tells a business whether demand for a particular type of product is expanding or shrinking, which influences decisions about investment and product development.
市场增长率衡量某个市场在一段时期内（通常为一年）规模的变化。它告诉企业，某类产品的需求是在扩大还是缩小，从而影响投资和产品开发的决策。
The formula compares the difference in market size between two periods with the original market size, then expresses the change as a percentage.
该公式将两个时期市场规模之差与原始市场规模进行比较，然后用百分比表示变化。
Market Growth (%) = [(Market Size in New Year – Market Size in Previous Year) ÷ Market Size in Previous Year] × 100
Example: The market for reusable water bottles was worth £12 million last year and is worth £14 million this year. Market growth = [(14 – 12) ÷ 12] × 100 = (2 ÷ 12) × 100 = 16.7%. This is a fast-growing market, which might attract new businesses.
示例：可重复使用水瓶的市场去年价值1200万英镑，今年价值1400万英镑。市场增长率 = [(14 – 12) ÷ 12] × 100 = (2 ÷ 12) × 100 = 16.7%。这是一个快速增长的市场，可能会吸引新企业进入。
A negative market growth rate indicates a shrinking market. A business operating in a shrinking market may need to diversify or find new ways to add value.
负的市场增长率表明市场在萎缩。在萎缩市场中经营的企业，可能需要进行多元化或寻找新的增值方式。
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