📚 Year 9 WJEC Business: Key Formulas and Principles Quick Reference Handbook | Year 9 WJEC 商务：公式定理速查手册
Mastering the essential formulas and principles is the foundation of success in WJEC Business. This quick reference guide brings together all the key equations and concepts you need to tackle calculations, analyse business performance, and ace your Year 9 assessments.
掌握关键的公式与原理是学好 WJEC 商务的基础。这本速查手册汇总了你在进行计算、分析企业表现以及应对九年级评估时所需的所有重要方程式与概念。
1. Revenue and Total Costs | 收入与总成本
Revenue is the income a business receives from its normal trading activities. It is calculated by multiplying the selling price of each unit by the quantity sold.
收入是企业从正常经营活动中获得的款项。它由每单位售价乘以销售数量计算得出。
Total Revenue = Selling Price per unit × Quantity sold
Total costs represent all the expenses incurred in producing goods or services. They are split into fixed costs and variable costs.
总成本表示生产产品或服务所发生的全部开支。它分为固定成本和变动成本。
Total Costs = Fixed Costs + Variable Costs
Fixed costs do not change with output in the short term (e.g., rent, insurance), while variable costs vary directly with the level of production (e.g., raw materials, packaging).
固定成本短期内不随产量变动（如租金、保险），而变动成本与生产水平直接成正比变化（如原材料、包装）。
2. Profit: Gross and Net | 利润：毛利润与净利润
Profit is the financial gain a business makes after all costs have been deducted from revenue. Gross profit focuses on direct trading activities.
利润是企业在扣除所有成本后从收入中获得的财务收益。毛利润关注的是直接的交易活动。
Gross Profit = Revenue − Cost of Sales
Cost of sales includes the direct costs of buying or making the goods sold, such as raw materials and direct labour. Net profit gives a fuller picture by also deducting indirect expenses.
销售成本包括采购或制造已售商品的直接成本，如原材料和直接人工。净利润通过扣除间接费用更全面地反映企业盈利。
Net Profit = Gross Profit − Operating Expenses
Operating expenses include overheads like salaries of office staff, marketing, rent, and utility bills. A positive net profit means the business is financially healthy.
营运费用包括管理人员薪金、市场推广、租金和水电费等经常开支。净利润为正数意味着企业财务健康。
3. Break-even Analysis | 盈亏平衡分析
The break-even point is the level of output at which total revenue equals total costs – the business makes neither a profit nor a loss. It is a vital planning tool.
盈亏平衡点是指总收入等于总成本时的产出水平，企业既不盈利也不亏损。这是一个重要的规划工具。
Break-even Point (units) = Fixed Costs ÷ (Selling Price per unit − Variable Cost per unit)
The term in brackets, Selling Price minus Variable Cost per unit, is known as the contribution per unit. It shows how much each sale contributes towards covering fixed costs and then towards profit.
括号中的售价减去每单位变动成本称为每单位贡献毛利。它表明每一笔销售在弥补固定成本后能为利润作出的贡献。
You can also calculate the break-even point in sales value: Break-even Sales = Break-even Units × Selling Price per unit.
你也可以计算以销售额表示的盈亏平衡点：盈亏平衡销售额 = 盈亏平衡单位数 × 每单位售价。
The margin of safety tells you how far sales can fall before the business starts losing money.
安全边际显示在开始亏损前销售额可以下降多少。
Margin of Safety = Actual Sales − Break‑even Sales
4. Profit Margins | 利润率
Profit margins express profit as a percentage of revenue, making it easier to compare performance over time or with competitors.
利润率将利润表示为收入的百分比，便于在不同时期或与竞争对手进行业绩比较。
Gross Profit Margin = (Gross Profit ÷ Revenue) × 100%
A high gross profit margin indicates the business is efficient at turning raw materials into sales revenue. The net profit margin takes all costs into account.
较高的毛利率表明企业高效地将原材料转化为销售收入。净利润率则考虑了所有成本。
Net Profit Margin = (Net Profit ÷ Revenue) × 100%
Improving profit margins often involves increasing selling prices, reducing costs, or boosting sales volume – but the best strategy depends on the market and the product.
提高利润率通常涉及提高售价、降低成本或增加销量，但最佳策略取决于市场和产品。
5. Average Cost and Economies of Scale | 平均成本与规模经济
Average cost per unit is the total cost of production divided by the number of units produced. It helps businesses set prices and forecast profits.
平均单位成本是总生产成本除以生产的单位数量。它帮助企业定价和预测利润。
Average Cost per unit = Total Costs ÷ Quantity Produced
As a business grows, it can often reduce its average cost through economies of scale – for example, buying raw materials in bulk for a lower price, or using specialised machinery more efficiently.
随着企业成长，通常可以通过规模经济降低平均成本，例如批量采购原材料获得更低价格，或更有效地使用专业机械。
However, if a firm grows too large, it may experience diseconomies of scale, where average cost rises due to communication problems or coordination difficulties.
然而，如果企业规模过大，可能会出现规模不经济，即由于沟通问题或协调困难导致平均成本上升。
6. Cash Flow Calculations | 现金流计算
Cash flow is the movement of money into and out of a business. A positive cash flow is essential to pay bills and avoid insolvency.
现金流是资金进出企业的流动。正向现金流对于支付账单、避免无力偿债至关重要。
Net Cash Flow = Total Cash Inflows − Total Cash Outflows
A cash flow forecast predicts future cash inflows and outflows over a period. The closing balance at the end of each month is worked out from the opening balance and net cash flow.
现金流量预测是在一段时间内预测未来的现金流入和流出。每月期末的结算余额由期初余额和净现金流计算得出。
Closing Balance = Opening Balance + Net Cash Flow
Inflows typically come from sales revenue, loans, or capital introduced by the owner. Outflows include payments for inventory, wages, rent, and loan repayments.
流入通常来自销售收入、贷款或所有者注入的资本。流出包括支付存货、工资、租金和偿还贷款。
7. Pricing Strategies: Mark-up and Margin | 定价策略：加成与毛利定价
Mark-up is the amount added to the cost price of goods to determine the selling price. It is usually expressed as a percentage of cost.
加成是在商品的成本价上增加的金额，用以确定售价。通常表示为成本的百分比。
Selling Price = Cost Price × (1 + Mark‑up percentage)
Alternatively, a business may set prices based on the margin – the percentage of the selling price that is profit. Margin and mark-up are different and must not be confused.
或者，企业可以根据利润率定价——即售价中利润所占的百分比。利润率与加成率不同，切勿混淆。
For example, if a product costs £10 and the desired mark-up is 50%, the selling price is £15. The profit margin is then £5/£15 ≈ 33.3%.
例如，若某产品成本为10英镑，期望的加成率为50%，则售价为15英镑。此时利润率为5/15 ≈ 33.3%。
8. Interest and Business Loans | 利息与商业贷款
Many businesses borrow money to fund expansion or manage cash flow. The cost of borrowing is interest, calculated on the principal amount.
许多企业借款用以资助扩张或管理现金流。借款成本是利息，按本金计算。
Simple Interest = Principal × Rate × Time
Rate is expressed as a decimal (e.g., 5% = 0.05) and time is in years. If a business borrows £10,000 for 3 years at 4% simple interest, the total interest is £1,200.
利率以小数表示（如5% = 0.05），时间以年为单位。若企业借款10,000英镑，为期3年，单利4%，则总利息为1,200英镑。
Compound interest, where interest is added to the principal so that future interest is earned on a growing amount, is also common – but it is more complex. At Year 9, simple interest is the main focus.
复利，即利息加入本金后利息也会产生利息，也很常见，但更为复杂。九年级主要关注单利。
9. Working Capital and Liquidity | 营运资金与流动性
Working capital measures the short-term financial health of a business. It shows whether current assets are sufficient to cover current liabilities.
营运资金衡量企业的短期财务健康状况。它表明流动资产是否足以支付流动负债。
Working Capital = Current Assets − Current Liabilities
Current assets include cash, inventory, and money owed by customers (trade receivables). Current liabilities are debts due within one year, such as trade payables and short‑term loans.
流动资产包括现金、存货和客户所欠的款项（应收账款）。流动负债是一年内到期的债务，如应付账款和短期贷款。
A positive working capital indicates good liquidity, meaning the business can pay its day‑to‑day bills without stress. Insufficient working capital may lead to cash flow crises.
正向的营运资金表明流动性良好，即企业能轻松支付日常账单。营运资金不足可能导致现金流危机。
10. Productivity Ratios | 生产率比率
Productivity measures how efficiently a business uses its resources, particularly labour. Higher productivity can lower average costs and improve competitiveness.
生产率衡量企业利用资源（尤其是劳动力）的效率。更高的生产率可以降低平均成本并提高竞争力。
Labour Productivity = Total Output ÷ Number of Employees
For instance, if a bakery produces 10,000 loaves with 10 workers, productivity is 1,000 loaves per worker. If the same output is achieved with 8 workers, productivity has risen.
例如，一家面包店用10名工人生产10,000个面包，每人生产率为1,000个。如果用8名工人实现同样产量，生产率就提高了。
Productivity can also be measured in terms of capital, such as output per machine hour. The principle remains the same: output divided by input.
生产率也可用资本衡量，如每机器小时产出。原理相同：产出除以投入。
11. Demand, Supply, and Market Equilibrium | 需求、供给与市场均衡
The law of demand states that, all else being equal, as the price of a good rises, the quantity demanded falls, and vice versa.
需求定律指出，在其他条件不变的情况下，商品价格上升，需求量下降，反之亦然。
The law of supply states that as the price of a good increases, the quantity supplied by producers also increases, because higher prices make production more profitable.
供给定律指出，商品价格上升，生产者愿意供给的数量也增加，因为更高的价格使生产更有利可图。
Market equilibrium occurs where the demand curve and supply curve intersect. At this point, quantity demanded equals quantity supplied, and there is no surplus or shortage.
市场均衡发生在需求曲线与供给曲线的交点。此时需求量等于供给量，不存在过剩或短缺。
Equilibrium: Quantity Demanded = Quantity Supplied
If the price is above equilibrium, a surplus results; if below, a shortage occurs. Market forces tend to push price back towards equilibrium.
如果价格高于均衡水平，就会出现过剩；如果低于均衡水平，则出现短缺。市场力量倾向于将价格推回均衡点。
12. Exchange Rates and Currency Conversion | 汇率与货币兑换
Businesses that trade internationally must deal with exchange rates. The exchange rate tells you how much of one currency you can get for another.
从事国际贸易的企业必须处理汇率问题。汇率说明用一种货币可以兑换多少另一种货币。
Cost in Foreign Currency = Amount in Home Currency × Exchange Rate
For example, if the exchange rate is £1 = $1.25, then £200 will buy $250. When a business imports goods, changes in the exchange rate affect the final cost.
例如，若汇率为1英镑 = 1.25美元，则200英镑可兑换250美元。企业进口商品时，汇率变动会影响最终成本。
A stronger pound makes imports cheaper and exports more expensive, while a weaker pound does the opposite. This directly impacts a business’s competitiveness overseas.
英镑走强使进口变便宜、出口变贵，而英镑走弱则反之。这直接影响企业在海外市场的竞争力。
Published by TutorHao | Business Revision Series | aleveler.com
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