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SingaporeAccountingSyllabus dot point

Which source document supports each transaction, and why must every entry start from one?

Identify the source documents for common transactions and explain their role in the accounting process

A focused answer to the O-Level Principles of Accounts outcome on source documents. The invoice, credit note, receipt, cheque counterfoil and others, and how each begins the recording process in the books of prime entry.

Generated by Claude Opus 4.87 min answer

Reviewed by: AI editorial process; not yet individually human-reviewed

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  1. What this dot point is asking
  2. The answer
  3. Examples in context
  4. Try this

What this dot point is asking

SEAB wants you to identify the source document for each common transaction and explain its role: every entry in the books begins with a source document. The central insight is that source documents are the evidence behind the records; they provide the accurate, dated, verifiable data that flows first into the books of prime entry and then into the ledgers.

The answer

What a source document is

A source document is the original piece of paper (or electronic record) that proves a transaction happened and gives its details: the date, the amount, and the parties involved. Accounting always starts from a source document so that the records are supported by evidence.

The common documents

Document When it is used Prepared by
Invoice Goods or services sold/bought on credit The seller
Credit note Goods returned, or an overcharge corrected The seller
Debit note Request for a credit note (claim for a return) The buyer
Receipt Money received The receiver
Cheque counterfoil A payment made by cheque The payer
Bank statement Listing of bank transactions The bank
Paying-in slip Money paid into the bank The payer

From document to book of prime entry

Each document feeds a specific book of prime entry (the first place a transaction is recorded), which is later posted to the ledgers:

  • Sales invoice (copy) - the sales journal.
  • Purchase invoice (received) - the purchases journal.
  • Credit note issued - the returns inwards journal.
  • Credit note received - the returns outwards journal.
  • Receipts, cheque counterfoils, paying-in slips - the cash book.

This is the start of the audit trail: document, then book of prime entry, then ledger, then trial balance, then financial statements.

Examples in context

Example 1. Tracing a disputed figure. A customer claims they were overcharged. Because the sale began with a sales invoice recorded in the sales journal, the business can produce the invoice as evidence and, if there really was an overcharge, issue a credit note to correct it. The source documents make the dispute easy to settle.

Example 2. Checking the bank. At month end the business compares its cash book (built from receipts and cheque counterfoils) with the bank statement from the bank. Differences such as bank charges are found by matching the two. Each side rests on source documents, which is what makes a bank reconciliation possible.

Try this

Q1. Name the source document for a credit sale and for a cash receipt. [2 marks]

  • Cue. A credit sale is supported by a sales invoice; a cash receipt by a receipt.

Q2. State the book of prime entry for a credit note issued to a customer. [1 mark]

  • Cue. The returns inwards (sales returns) journal.

Q3. Explain one risk of recording transactions without source documents. [2 marks]

  • Cue. Without evidence, the business could record wrong amounts, omit real transactions, or record ones that never happened, so errors and fraud become hard to detect.

Exam-style practice questions

Practice questions written in the style of SEAB exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

Original6 marksState the source document that would support each transaction, and the book of prime entry it would be recorded in: (a) goods sold on credit; (b) goods returned by a customer; (c) goods bought on credit; (d) cash received from a customer.
Show worked answer →
Transaction Source document Book of prime entry
Goods sold on credit Sales invoice (copy) Sales journal
Goods returned by a customer Credit note (issued) Returns inwards journal
Goods bought on credit Purchase invoice (received) Purchases journal
Cash received from a customer Receipt (copy) Cash book

Markers reward the correct source document and the correct book of prime entry for each transaction, recognising that an invoice supports a credit sale or purchase and a credit note supports a return.

Original4 marksExplain why a business records every transaction from a source document, and what could go wrong if it did not.
Show worked answer →

A source document is the original evidence that a transaction took place, such as an invoice, receipt or cheque counterfoil. Recording from it ensures every entry is supported by proof, gives the correct amount, date and parties, and creates an audit trail so entries can be checked later.

If a business recorded transactions without source documents, it could make errors in the amounts or dates, record transactions that never happened, or omit real ones. There would be no evidence to verify the books, making fraud and mistakes hard to detect and the accounts unreliable.

Markers reward defining a source document as the original evidence, explaining that it gives accurate, verifiable data and an audit trail, and noting the risk of errors, omissions or fraud without it.

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