📒 Accounting I

What you’ll learn

1. One Idea Generates EverythingState the single idea underlying double-entry — that every resource has a source, so every event has two descriptions — and show that it admits no exceptions.Accounting is usually taught as a pile of arbitrary rules, but it is one observation: anything a business has came from somewhere, so every event can be described twice — what it is and where it came from. The two descriptions cannot disagree because they describe the same thing, and even apparent exceptions like swapping cash for equipment have an internal source. Luca Pacioli documented the method in 1494 rather than inventing it, and it has survived unchanged for five centuries because it describes a fact about reality rather than a convention.
2. The Equation Is the Idea, Written DownShow that Assets = Liabilities + Equity is the Chapter 1 idea written down, and define equity as a residual rather than a pot of money.The accounting equation is not a formula to memorise but one pile of value counted twice: the left lists what the business has, the right lists where it came from, sorted by whether outsiders or owners have the claim. It cannot fail to balance because both sides describe the same value. Equity is a residual — assets minus liabilities — which is why it can be negative, and its retained earnings component is where profit lives: earning simply means the right-hand side growing without anyone putting money in.
3. Debits and Credits Are Not Good and BadStrip debits and credits of false meaning, justify the convention by its error-detection value, and derive the increase/decrease rule from the equation.Debit means left and credit means right — from the Latin used by Venetian merchants — and neither carries any implication of good, bad, increase or decrease. The convention persists because putting the two descriptions on opposite sides turns Chapter 1's impossibility into arithmetic, giving an error-detection system built into the notation. The single rule is that accounts increase on the side of the equation they live on, so assets increase with debits while liabilities and equity increase with credits, and revenue and expenses follow because they are equity in motion.
4. The Journal EntryWrite journal entries — including compound entries — and explain the relationship between the journal and the ledger.A journal entry records one event with debits equal to credits, and reads as a sentence: we have more of this, and it came from that. Double-entry means two sides rather than two accounts, so a compound entry may touch many accounts provided the totals match. The journal orders events by time and the ledger sorts the identical information by account, which is why you enter once and it lands twice — and entries are never erased, only corrected by further entries, which is what makes books auditable.
5. Follow One Business All the Way ThroughApply the whole system to a complete first year of trading and observe that the equation holds after every entry and that the statements require no new machinery.Perch Coffee's first year — an owner's £30,000, a £12,000 loan, an £18,000 cart, £24,000 of supplies on credit, £95,000 of sales, and the costs of trading — runs entirely on Chapter 1's idea, with the equation holding after each of the nine events rather than being corrected at year end. Buying the cart leaves total assets unchanged because one asset became another, while paying suppliers shrinks both sides and leaves the business no poorer. By year end the accounts already contain all three statements, because the statements are sorts of the same pile of entries rather than separate reports.
6. Why It Balances — and Why That Doesn't Mean It's RightExplain what a trial balance proves, enumerate the errors it cannot detect, and draw the distinction between balancing and being true.Summing individually balanced entries necessarily gives equal debit and credit totals, so a trial balance proves arithmetical consistency and nothing more. It is silent about transactions never recorded, correct amounts posted to wrong accounts, duplicated entries, offsetting errors, and identical transpositions on both sides — so wages misposted to Equipment leave the books balanced while overstating profit. Double-entry catches recording errors automatically but cannot catch errors of judgement or omission, which is why auditors, standards and notes exist on top of the mechanism.
7. The Balance Sheet Is a PhotographRead a balance sheet as a moment-in-time statement of position, interpret each side's ordering, and understand why it is not a valuation.'As at' signals a photograph: the balance sheet shows position at an instant and says nothing about the path taken, so every history ending in the same position produces the same statement. Assets are ordered by liquidity and claims by urgency, so the information lies in the composition of each side and their relationship rather than in the fact of balancing. Because assets are recorded at cost less depreciation rather than at worth, a balance sheet is not a valuation — and everything never purchased in a transaction, such as a built reputation, is absent by design.
8. The Income Statement Is a FilmRead an income statement as a period statement, explain why its lines are ordered as narrowing questions, and connect net income to retained earnings.The income statement covers a period rather than a moment, and its stacking — gross profit, operating profit, net income — is a sequence of narrowing questions about whether the product, the business, and then the financed business make money. Cost of goods sold counts only what was consumed, so unsold inventory remains an asset to be matched against future revenue. Net income flows into retained earnings, which makes the income statement the detailed working behind one line of the balance sheet, and explains why revenue and expense accounts reset each period while balance sheet accounts carry forward.
9. Accrual: When Did It Actually Happen?Explain accrual accounting — revenue recognition and matching — and why it is required despite cash accounting being more objective.Cash accounting is unfalsifiable but lies about time: it splits one economic event across periods and lets profit be manufactured by moving payment dates, so a business that stops paying suppliers appears more profitable. Accrual insists the economics choose the period, recognising revenue when earned and matching costs to the revenue they produced. The accounts receivable line is the gap between earning and collecting made visible — and its existence means profit and cash have come apart and can stay apart indefinitely.
10. Depreciation and the Matching IdeaDerive depreciation from the matching principle, perform straight-line calculation, and recognise that useful-life estimates are judgements that move reported profit.Buying a long-lived asset consumes nothing — one asset becomes another — so it does not touch profit, but the asset is consumed gradually as it earns and its cost must be recognised the same way. Charging it all at purchase or all at disposal both misplace the cost, so straight-line depreciation spreads it across the periods it helps produce revenue, crediting a separate accumulated depreciation account to preserve both cost and consumption as distinct facts. No cash moves, making it the clearest demonstration that profit is not cash, and because useful life and residual value are judgements, they are a legitimate and substantial lever on reported earnings.
11. Why Profit Is Not MoneyExplain why profit and cash diverge, demonstrate overtrading, and construct an indirect cash flow statement as a reconciliation.Profit answers whether more was earned than consumed and requires judgement; cash answers whether money is in the account and requires none — and a business survives an unprofitable year but not a payroll it cannot meet. Growth consumes cash because costs are paid before customers pay, so Perch's Year 2 shows £40,000 of profit and negative £12,000 from operations purely because receivables rose £55,000, with the income statement giving no warning because it is correct. The indirect cash flow statement bridges the two by starting at net income and undoing every accrual — adding back depreciation, subtracting rises in receivables and inventory, adding rises in payables — then reporting investing and financing separately.
12. The Three Statements Are One SystemDemonstrate that the three statements are three sorts of one pile of entries, identify the three points at which they touch, and trace an event through all of them.The statements are not three reports that happen to link but three sorts of the same journal entries, which is why they cannot disagree. They touch at three places: net income lands in retained earnings, the cash flow statement begins at net income, and ending cash is the balance sheet's cash line — forming a closed system in which no number can move alone. Tracing a £5,000 bad-debt write-off shows receivables and retained earnings both falling while cash from operations is unchanged, because no cash was ever received, and reading all three together is what allows a reader to triangulate what a business is actually doing.
13. What the Numbers Cannot Tell YouIdentify the judgements underlying apparently exact accounts, explain why balancing does not imply truth, and articulate accounting's reliability-over-relevance trade.Every figure in a set of accounts rests on judgements — useful life, residual value, depreciation method, collectability, when revenue was earned — each defensible, each an opinion about an uncertain future, and each capable of moving the reported numbers. Double-entry makes the arithmetic consistent, which makes estimates look computed, and every major scandal involved immaculately balanced books where the dispute was about judgement rather than arithmetic. Accounting records only what a transaction verified, so a built reputation appears nowhere while a purchased one becomes goodwill — a deliberate choice of reliability over relevance, preferring the verifiable and incomplete to the comprehensive and unverifiable.

Questions this course answers

Grounded in trusted sources

• Weygandt, Kimmel & Kieso, Financial Accounting (Wiley)
• Horngren, C., Harrison, W. & Oliver, S., Accounting (Pearson)
• Pacioli, L., Summa de Arithmetica, Geometria, Proportioni et Proportionalita (Venice, 1494)
• Gleeson-White, J., Double Entry: How the Merchants of Venice Created Modern Finance (W. W. Norton, 2012)
• IFRS Foundation — Conceptual Framework for Financial Reporting (2018)
• IFRS Foundation — IAS 1 Presentation of Financial Statements
• IFRS Foundation — IAS 7 Statement of Cash Flows
• IFRS Foundation — IAS 16 Property, Plant and Equipment

Every Wunder lesson is built from real, reputable sources — never invented.

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