📚 Year 9 SQA Business: Formula & Theorem Quick Reference | SQA九年级商务：公式定理速查手册
This quick reference handbook brings together all the essential formulas, ratios and fundamental theorems you need for Year 9 SQA Business. From revenue and cost calculations to break-even analysis and liquidity ratios, each entry is explained step by step so you can use it confidently in classwork, homework and assessments.
本速查手册汇集了 SQA 九年级商务课程所需的所有核心公式、比率和基础定理。从收入与成本计算到收支平衡分析和流动性比率，每个条目都配有逐步解释，方便你在课堂练习、作业和测评中自信运用。
1. Revenue Formula | 收入公式
Revenue = Price per unit × Quantity sold
Revenue is the money a business brings in from selling its goods or services before any costs are deducted. It is sometimes called turnover or sales revenue. If a bakery sells 200 cupcakes at £2.50 each, its revenue is £500. Revenue is a top-line figure on the income statement and is vital for measuring business size and growth.
收入是企业在扣除任何成本之前通过销售商品或服务所获得的金额，有时也称为营业额或销售收入。如果一家面包店以每块 2.50 英镑的价格售出 200 个杯子蛋糕，其收入就是 500 英镑。收入是损益表中的第一行数字，对衡量企业规模和增长至关重要。
2. Total Costs: Fixed and Variable | 总成本：固定成本与变动成本
Total Cost = Total Fixed Cost + Total Variable Cost
Every business faces two main types of cost. Fixed costs stay the same regardless of output – think rent, salaries and insurance. Variable costs change directly with production and sales, such as raw materials, packaging and piece-rate wages. Total variable cost is found by multiplying the variable cost per unit by the number of units produced. Knowing total cost helps managers set prices and forecast profit.
每个企业都面临两大类成本。固定成本不随产量变化——例如租金、管理人员薪金和保险费。变动成本直接随生产和销售变动，比如原材料、包装和计件工资。总变动成本等于单位变动成本乘以生产数量。掌握总成本有助于管理者制定价格和预测利润。
3. Profit Calculation | 利润计算
Profit = Total Revenue − Total Cost
Profit is the financial reward for taking a business risk. It is what remains after all costs are paid out of revenue. Profit can be positive (profit), zero (break-even) or negative (loss). Businesses use profit to reinvest, pay dividends or build reserves. A consistent profit signals a healthy, sustainable enterprise.
利润是对承担商业风险的财务回报。它是从收入中扣除所有成本后剩余的部分。利润可以是正值（盈利）、零（收支平衡）或负值（亏损）。企业利用利润进行再投资、支付股息或建立储备金。持续盈利标志着企业健康、可持续发展。
4. Gross Profit Margin | 毛利率
Gross Profit = Revenue − Cost of Sales
Gross Profit Margin = (Gross Profit ÷ Revenue) × 100%
Gross profit shows how much money is left after paying the direct costs of making a product or providing a service. The gross profit margin turns this into a percentage, making it easy to compare across periods or with competitors. For example, if a business earns £100,000 in revenue and its cost of sales is £60,000, the gross profit is £40,000 and the margin is 40%. A high gross margin suggests strong pricing power or efficient production.
毛利润显示在支付了生产产品或提供服务的直接成本之后还剩多少钱。毛利率将这个数字转化为百分比，便于与历史同期或竞争对手比较。例如，某企业收入为 100,000 英镑，销售成本为 60,000 英镑，则毛利润为 40,000 英镑，毛利率为 40%。较高的毛利率往往意味着定价能力强或生产效率高。
5. Net Profit Margin | 净利率
Net Profit = Gross Profit − Expenses
Net Profit Margin = (Net Profit ÷ Revenue) × 100%
Net profit is the final profit after deducting all other expenses such as rent, advertising, salaries and interest. The net profit margin reveals what percentage of each pound earned ends up as clear profit. If a firm has a gross profit of £40,000 and total expenses of £25,000, net profit is £15,000. With revenue of £100,000, the net margin is 15%. This ratio is a key indicator of overall efficiency and cost control.
净利润是扣除所有其他费用（如租金、广告、薪金和利息）之后的最终利润。净利率显示了每赚取一英镑收入最终能形成多少真正的利润。如果一家企业的毛利润为 40,000 英镑，总费用为 25,000 英镑，则净利润为 15,000 英镑。若收入为 100,000 英镑，净利率就是 15%。该比率是衡量整体效率和成本控制的关键指标。
6. Break-even Point | 收支平衡点
-even point (units) = Total Fixed Cost ÷ (Selling Price per unit − Variable Cost per unit)
The break-even point is the level of sales where total revenue exactly equals total cost – the business makes neither profit nor loss. The denominator is called contribution per unit, the amount each sale contributes to covering fixed costs. For instance, fixed costs of £10,000, a selling price of £25 and a variable cost of £15 give a break-even output of 1,000 units. Break-even analysis helps businesses set targets and decide whether to launch a new product.
收支平衡点是指总收入恰好等于总成本时的销售水平——企业既不盈利也不亏损。分母称为单位贡献毛利，即每笔销售对覆盖固定成本的贡献额。例如，固定成本为 10,000 英镑，售价为 25 英镑，变动成本为 15 英镑，则收支平衡产量为 1,000 件。收支平衡分析有助于企业设定目标并决定是否推出新产品。
7. Current Ratio | 流动比率
Current Ratio = Current Assets ÷ Current Liabilities
The current ratio measures a business's ability to pay short-term debts (due within one year) from its short-term assets. Current assets include cash, inventory and receivables; current liabilities include overdrafts and payables. A ratio of 2:1 is often considered healthy, but acceptable figures vary by industry. A ratio below 1 suggests liquidity problems, while a very high ratio may indicate idle resources.
流动比率衡量企业用短期资产偿还一年内到期短期债务的能力。流动资产包括现金、存货和应收账款；流动负债包括银行透支和应付账款。通常认为 2:1 是健康的比率，但不同行业标准有所不同。比率低于 1 可能暗示流动性问题，而过高的比率或许说明资源闲置。
8. Acid Test Ratio (Quick Ratio) | 酸性测试比率（速动比率）
Acid Test Ratio = (Current Assets − Inventories) ÷ Current Liabilities
The acid test ratio is a stricter measure of liquidity because it excludes inventories, which may be hard to turn into cash quickly. Ideally this ratio should be at least 1:1, though many successful businesses operate with a slightly lower figure. A very low acid test ratio can signal a cash-flow crisis if sales slow down unexpectedly.
酸性测试比率是更严格的流动性指标，因为它剔除了存货，后者可能难以快速变现。理想状态下该比率至少应为 1:1，不过许多成功的企业在稍低的比率下仍能良好运营。如果酸性测试比率过低，一旦销售意外放缓，就可能预示现金流危机。
9. The Law of Demand | 需求定律
The Law of Demand states that, all other things being equal, as the price of a product increases, the quantity demanded decreases, and vice versa. This inverse relationship is driven by the income effect (higher prices reduce purchasing power) and the substitution effect (consumers switch to cheaper alternatives). Demand is represented by a downward-sloping curve on a price–quantity graph.
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；价格下降，需求量上升。这种反向关系由收入效应（价格升高降低购买力）和替代效应（消费者转向更便宜的替代品）驱动。在价格-数量图上，需求表现为一条向右下方倾斜的曲线。
10. The Law of Supply | 供给定律
The Law of Supply states that as the price of a product rises, the quantity supplied increases, ceteris paribus. Producers are willing to supply more when they can earn higher revenue per unit, which may cover rising marginal costs. This direct relationship gives an upward-sloping supply curve.
供给定律指出，在其他条件相同的情况下，商品价格上升，供给量增加。当每单位产品能带来更高收入时，生产者愿意增加供给，这足以覆盖不断上升的边际成本。这种正向关系形成了一条向上倾斜的供给曲线。
11. Opportunity Cost | 机会成本
Opportunity cost is the value of the next best alternative that must be given up when a choice is made. It is a central concept in business decisions – choosing one investment means sacrificing potential returns from another. For example, if a teenager spends £10 on a cinema ticket, the opportunity cost might be the two lunch deals they could have bought instead.
机会成本是指做出某一选择时所必须放弃的次优替代方案的价值。它是商务决策中的核心概念——选择一项投资就意味着牺牲来自其他投资可能带来的回报。例如，一个青少年花 10 英镑买电影票，其机会成本可能就是原本可以用这笔钱买到的两份午餐套餐。
12. Return on Investment (ROI) | 投资回报率
ROI = (Net Profit from Investment ÷ Capital Invested) × 100%
Return on Investment evaluates how much profit is generated from a specific amount of invested capital. A positive ROI means the investment is profitable. If you invest £5,000 in new equipment and generate an additional £1,500 net profit in one year, the ROI is 30%. Businesses compare ROI across projects to prioritise spending.
投资回报率衡量从特定投资额中产生了多少利润。正值意味着投资盈利。如果你投资 5,000 英镑购买新设备，并在一年内额外创造了 1,500 英镑净利润，则投资回报率为 30%。企业通过对比不同项目的 ROI 来安排支出优先顺序。
Published by TutorHao | Business Revision Series | aleveler.com
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