📚 IGCSE CIE Accounting: Formulas & Theorems Quick Reference Handbook | IGCSE CIE 会计：公式定理速查手册
This quick reference handbook brings together the essential formulas, principles, and double‑entry rules you need to master for the IGCSE CIE Accounting examination. Use it to review and check key concepts efficiently.
本速查手册汇集了IGCSE CIE会计考试所需的必备公式、定理和复式记账规则，帮助你高效复习和查阅重要概念。
1. The Accounting Equation | 会计等式
The accounting equation is the foundation of double‑entry bookkeeping and states that total assets must always equal the sum of liabilities and capital (owner's equity).
会计等式是复式记账的基础，表明总资产必须始终等于负债与资本（所有者权益）之和。
Assets = Liabilities + Capital
An alternative presentation is Assets – Liabilities = Capital, which highlights the net assets owned by the proprietor. After every transaction the equation remains in balance.
另一种表达方式为资产 – 负债 = 资本，突出了业主拥有的净资产。每笔交易后等式依然保持平衡。
2. Rules of Double‑Entry | 复式记账规则
Every transaction has a dual effect, recorded as one debit entry and one credit entry. The rules for increases are summarised below.
每笔交易都有双重影响，记录为一项借方分录和一项贷方分录。以下是有关增加的规则总结。
Increases in assets and expenses are debited; decreases are credited.
资产和费用的增加记入借方，减少记入贷方。
Increases in liabilities, capital (including drawings), and income are credited; decreases are debited.
负债、资本（包括提款）和收入的增加记入贷方，减少记入借方。
Total debits must equal total credits for every transaction and for the entire ledger.
每笔交易以及整个分类账的借方总额必须等于贷方总额。
3. Computation of Profit & Loss | 损益计算
Gross profit is the difference between sales revenue and the cost of goods sold. Net profit takes account of all other income and expenses.
毛利是销售收入与销货成本之间的差额。净利润则考虑了所有其他收入和费用。
Gross Profit = Sales Revenue – Cost of Goods Sold
Net Profit = Gross Profit + Other Income – Expenses
The income statement (profit and loss account) is structured to show gross profit first, then operating expenses, before arriving at net profit.
利润表（损益表）的结构首先显示毛利，然后列示营业费用，最后得出净利润。
4. Cost of Goods Sold (COGS) | 销货成本
COGS represents the direct cost of the goods that were sold during the period. It is calculated by adjusting purchases for opening and closing inventories.
销货成本表示当期已售商品的直接成本。它通过对购货进行期初期末库存调整计算得出。
COGS = Opening Inventory + Net Purchases – Closing Inventory
Net purchases are calculated as Purchases – Purchases Returns + Carriage Inwards. Carriage outwards is a selling expense, not part of COGS.
购货净额计算为购货 – 购货退回 + 购货运费。销货运费属于销售费用，不计入销货成本。
5. Profitability Ratios | 盈利能力比率
Profitability ratios measure how successfully a business generates profit from its operations and capital. Key formulas are:
盈利能力比率衡量企业通过经营和资本获取利润的能力。主要公式如下：
