Why is "Putting discount allowed on the Dr side of the SLCA." a common mistake in Control accounts?

Why it happens: Students associate 'discount allowed' with the income statement expense (which IS Dr). How to avoid it: In the SLCA, discount allowed REDUCES the customer's debt → Cr. (The Dr is in the Discount Allowed expense account elsewhere.) Source: Edexcel 4AC1 examiner reports.

Why is "Putting returns inwards on the Dr side of the SLCA." a common mistake in Control accounts?

Why it happens: Returns inwards is Dr in the TB. How to avoid it: In the SLCA, returns REDUCE the customer's debt → Cr.

Why is "Treating the control account as if it replaces the personal ledgers." a common mistake in Control accounts?

Why it happens: Misunderstanding of role. How to avoid it: Personal ledgers (SL and PL) hold individual customer/supplier accounts. The control account is a TOTAL — it doesn't replace the detail. Both are kept.

Why is "Putting set-offs on the wrong side." a common mistake in Control accounts?

Why it happens: Direction confusion. How to avoid it: Set-off reduces what each side owes. Cr SLCA (customer's debt reduced) and Dr PLCA (supplier's debt reduced) — both on the side that reduces the balance.

Why is "Putting irrecoverable debts on the Dr side of the SLCA." a common mistake in Control accounts?

Why it happens: Students think of it as 'the loss'. How to avoid it: Writing off REMOVES the customer's debt → Cr SLCA. The Dr is in Irrecoverable Debts expense.

Why is "Putting a refund to a customer on the Cr side." a common mistake in Control accounts?

Why it happens: Students see 'money going out' and think Cr Bank Dr Customer — but for the SLCA, the customer is OWED MORE (negative debt becomes a refund obligation). How to avoid it: A refund INCREASES what the business owes to the customer → Dr SLCA. (Bank is Cr, as usual for a payment.)

Introduction to control processesPearson Edexcel IGCSE Accounting 4AC1

Control accounts

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Control Accounts — Edexcel IGCSE Accounting (4AC1) Detailed Notes

The Sales Ledger Control Account (SLCA) and Purchases Ledger Control Account (PLCA) — totals-only summary accounts that cross-check the personal ledgers and feed directly into the SOFP.

What you’ll learn

Mapped to the Pearson Edexcel IGCSE 4AC1 syllabus (2026 onwards).

Explain the purpose of control accounts and the benefits to a business.
Identify the items that appear on each side of the SLCA and PLCA.
Prepare a Sales Ledger Control Account and Purchases Ledger Control Account in T-account format.
Reconcile a control account with the corresponding personal ledger total and identify causes of discrepancy.
Use control accounts to find missing figures (e.g., credit sales, credit purchases).

Purpose and benefits of control accounts

Error detection · separation of duties · efficient SOFP preparation · time-saving.

1. Error detection. If the SLCA closing balance ≠ Sales Ledger total, there is an error in one or both — providing an early-warning system.

2. Separation of duties. The control account is typically kept by a senior accountant, while customer/supplier ledgers are kept by junior staff. Two different people working on the same data make fraud and unauthorised entries harder.

3. Direct input to SOFP. Trade Receivables and Trade Payables figures come straight from the SLCA and PLCA closing balances — no need to add up every customer/supplier balance.

4. Speed up trial balance. Instead of listing every customer (potentially hundreds), the TB just shows two figures — the control account balances.

5. Snapshot of the business's debtor/creditor position. Useful for management decisions on credit control, cash flow planning, ratio analysis.

Detect errors in personal ledgers.
Enforce separation of duties → reduces fraud.
Direct line to SOFP figures.
Trial balance becomes a manageable summary.
Management oversight of receivables/payables.

The Sales Ledger Control Account (SLCA)

Total trade receivables — the 'super-customer' account.

The SLCA aggregates every customer account in the Sales Ledger. Like a customer account:

Dr side (increases the debt):

Opening balance (b/d)
Credit Sales (from Sales Day Book total)
Bank refund to a customer (overpayment)
Dishonoured cheque (cheque returned by bank — customer's debt is reinstated)
Interest charged on overdue accounts

Cr side (reduces the debt):

Cheques and cash received from customers
Returns Inwards (from Sales Returns Day Book total)
Discount Allowed (from Cash Book discount column total)
Irrecoverable Debts written off
Set-off / contra-entry (transferred to PLCA)

Closing balance c/d is on the smaller side; balance b/d appears on the opposite side the next period.

SLCA aggregates all customer accounts — closing balance b/d is the Trade Receivables figure on the SOFP.

The Purchases Ledger Control Account (PLCA)

Total trade payables — the 'super-supplier' account.

The PLCA is the mirror of the SLCA — it aggregates every supplier account.

Cr side (increases the debt to suppliers):

Opening balance (b/d)
Credit Purchases (from Purchases Day Book total)

Dr side (reduces the debt):

Cheques and cash paid to suppliers
Returns Outwards
Discount Received
Set-off / contra-entry

Closing balance c/d is on the Dr (smaller) side; balance b/d is on the Cr side next period — because trade payables is a liability.

Set-offs (contra-entries) — when a party is both customer and supplier

Cancel out mutual debts in both control accounts.

When a single business is both a customer AND a supplier (e.g., J Khan sells to your business AND buys from your business), you can SET OFF the lower amount against the higher to simplify cash management.

Example: J Khan owes the business £400 (in SLCA). The business owes J Khan £600 (in PLCA). Set-off £400:

Dr PLCA (J Khan) £400 — reduces what the business owes him.
Cr SLCA (J Khan) £400 — reduces what he owes the business.

After set-off: J Khan now owes nothing on the SL side, and is owed £200 net on the PL side. Only £200 will actually be paid in cash.

Side rules:

In the SLCA, set-off appears on the Cr side (reduces customer's debt).
In the PLCA, set-off appears on the Dr side (reduces supplier's debt).

Reconciling the control account with the personal ledger

Match the control account balance to the total of individual customer/supplier balances.

Standard procedure:

Total all individual customer balances in the Sales Ledger.
Compare with the SLCA closing balance.
If they agree → no error.
If they disagree → investigate.

Common causes of disagreement:

Posting errors: an invoice posted to one but missed from the other.
Casting errors: wrong addition in the Sales Day Book total OR in summing up the Sales Ledger balances.
Wrong side: an entry made on the Dr side in one but Cr in the other.
Transposition: a balance written as £570 in the SL but recorded as £750 in the control account.
Omission: an irrecoverable debt written off in the SL but missed from the SLCA.

Adjustment side: errors in the Sales Day Book total or Cash Book total affect the CONTROL account (since totals are posted there). Errors in individual customer accounts affect the SALES LEDGER total.

Using control accounts to derive missing figures (preview)

If you know opening, closing and most movements, you can solve for the missing one.

In incomplete records (Topic 4.3), control accounts are used IN REVERSE — to derive a missing figure.

Finding credit sales: Credit Sales = Closing SLCA − Opening SLCA + Receipts + Returns Inwards + Discount Allowed + Irrecoverable Debts

Finding credit purchases: Credit Purchases = Closing PLCA − Opening PLCA + Payments + Returns Outwards + Discount Received

Why this works: the formulae are simply rearrangements of the control-account identity.

How it’s examined

Paper 1: State which side items appear on (4–6 marks); explain benefits (4–6 marks).

Paper 2: Prepare a full SLCA or PLCA in T-account form (8–10 marks); reconcile and explain discrepancies (8 marks); derive a missing figure in an incomplete-records question (4–6 marks).

Sources: Pearson Edexcel International GCSE in Accounting (4AC1) Specification — Issue 3; Edexcel 4AC1 Examiner Reports (2022–2024). Last reviewed 2026-05-19.

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Step-by-step worked examples — Control accounts

Step-by-step solutions to past-paper-style questions on control accounts, written exactly the way a tutor would explain them at the board.

1State which side of the SLCA each item appears on
Getting started• Edexcel 4AC1 style — short-answer (5 marks)• SLCA, AO1
Question
State Dr or Cr in the Sales Ledger Control Account (SLCA): (a) Credit sales £10,000. (b) Cash received from customers £8,000. (c) Returns inwards £400. (d) Discount allowed £150. (e) Irrecoverable debts written off £200.
Step-by-step solution
1. Step 1
  SLCA mirrors a customer's account: things that INCREASE the debt are Dr; things that REDUCE it are Cr.
Answer
(a) Dr (sales increase customer's debt).

(b) Cr (payments reduce debt).

(c) Cr (returns reduce debt).

(d) Cr (discount reduces debt).

(e) Cr (write-off removes the debt).
Examiner tip
Think of the SLCA as a 'total customers' account. Anything that customers OWE more = Dr. Anything that REDUCES what they owe = Cr.
2State which side of the PLCA each item appears on
Getting started• Edexcel 4AC1 style — short-answer (5 marks)• PLCA, AO1
Question
State Dr or Cr in the Purchases Ledger Control Account (PLCA): (a) Credit purchases £6,000. (b) Cash paid to suppliers £4,500. (c) Returns outwards £200. (d) Discount received £80. (e) Set-off / contra-entry £150.
Step-by-step solution
1. Step 1
  PLCA mirrors a supplier's account: things that INCREASE the debt to suppliers are Cr; things that REDUCE it are Dr.
Answer
(a) Cr (purchases increase debt to supplier).

(b) Dr (payments reduce debt).

(c) Dr (returns reduce debt).

(d) Dr (discount reduces debt).

(e) Dr (set-off reduces debt — transferred against SLCA).
Examiner tip
PLCA is the mirror of SLCA. A customer/supplier set-off (Dr SLCA / Cr PLCA — or vice versa) appears on the SAME side as a payment to / from that party.
3Identify reasons for SLCA and Sales Ledger balance mismatch
Higher• Edexcel 4AC1 style — short-answer (5 marks)• reconciliation, AO1, AO2
Question
The SLCA balance is £15,200. The total of customer balances in the Sales Ledger is £15,400. State five possible reasons for this discrepancy.
Step-by-step solution
1. Step 1
  Differences arise from posting errors. Either the control account or the individual customer accounts has been incorrectly updated.
Answer
Possible reasons:

An invoice posted to the Sales Day Book (and thus to the SLCA total) but missed from a customer's account.

A returns inwards entered in a customer's account but missed from the Sales Returns Day Book total.

A cheque receipt entered in the customer's account but missed from the Cash Book total.

A casting error (wrong addition) in the Sales Day Book total or in the Sales Ledger total.

A balance brought down on the wrong side in a customer's account.
Examiner tip
Mark schemes accept any reasonable category of error. The £200 difference here may be the COMBINED effect of multiple errors; investigation is needed to identify the specific entries.
4Calculate the closing balance of the SLCA
Building confidence• Edexcel 4AC1 style — calculation (5 marks)• SLCA, calculation, AO1, AO2
Question
From the following data, calculate the closing SLCA balance:

Opening Dr balance £8,400.

Credit sales £25,000.

Cash received from customers £21,500.

Returns inwards £600.

Discount allowed £200.

Irrecoverable debts written off £300.
Step-by-step solution
1. Step 1
  Use Closing = Opening + Sales − Receipts − Returns − Discounts − Write-offs.
Answer
Closing SLCA balance = £8,400 + £25,000 − £21,500 − £600 − £200 − £300 = £10,800 Dr

Customers collectively owe the business £10,800.
Examiner tip
Always present the calculation in T-account form when the question asks for the account. The closing balance c/d is on the smaller side, b/d on the opposite side.
5Calculate the closing balance of the PLCA
Building confidence• Edexcel 4AC1 style — calculation (5 marks)• PLCA, calculation, AO1, AO2
Question
From the following data, calculate the closing PLCA balance:

Opening Cr balance £4,200.

Credit purchases £18,000.

Cash paid to suppliers £15,000.

Returns outwards £400.

Discount received £120.

Set-off against SLCA £250.
Step-by-step solution
1. Step 1
  Use Closing = Opening + Purchases − Payments − Returns − Discounts − Set-offs.
Answer
Closing PLCA balance = £4,200 + £18,000 − £15,000 − £400 − £120 − £250 = £6,430 Cr

The business collectively owes suppliers £6,430.
Examiner tip
Set-off entries (when a customer is also a supplier) appear on BOTH control accounts on the side that REDUCES the balance.
6Calculate a missing credit sales figure from the SLCA
Higher• Edexcel 4AC1 style — calculation (5 marks)• missing-figure, SLCA, AO1, AO2
Question
The SLCA opening balance was £7,500 and closing balance £9,800. During the period: receipts from customers £30,000; returns inwards £450; discount allowed £150; irrecoverable debts £200. Calculate the credit sales for the period.
Step-by-step solution
1. Step 1
  Rearrange: Credit Sales = Closing − Opening + Receipts + Returns + Discounts + Write-offs.
Answer
Credit Sales = £9,800 − £7,500 + £30,000 + £450 + £150 + £200 = £33,100
Examiner tip
Working backwards from the SLCA is a classic 4AC1 Paper 2 technique — central to incomplete records (Topic 4.3) where credit sales are often the missing figure.

7Prepare the SLCA in T-account format

Higher• Edexcel 4AC1 style — extended (8 marks)• SLCA-format, AO1, AO2

Question

Prepare the SLCA for the month of May 2026 in T-account format. Opening balance £5,200 Dr. Transactions in May: credit sales £18,000; cheques from customers £14,500; cash from customers £900; returns inwards £400; discount allowed £180; irrecoverable debts written off £350; refund to customer £100.

Step-by-step solution

Step 1
Set up T-account, post each item to correct side, balance off.

Answer

Sales Ledger Control Account (May 2026)

Dr			Cr
Date	Details	£	Date	Details	£
1/5	Balance b/d	5,200	31/5	Bank	14,500
31/5	Sales	18,000	31/5	Cash	900
31/5	Bank (refund)	100	31/5	Returns Inwards	400
			31/5	Discount Allowed	180
			31/5	Irrecoverable Debts	350
			31/5	Balance c/d	6,970
		23,300			23,300
1/6	Balance b/d	6,970

Closing SLCA = £6,970 Dr.

Examiner tip

A refund to a customer (e.g., for overpayment) appears on the Dr side of the SLCA — it INCREASES what is owed back. A* candidates show the refund correctly.

8Reconcile the SLCA with the Sales Ledger total after errors
Stretch• Edexcel 4AC1 style — extended (10 marks)• reconciliation, AO1, AO2, AO3
Question
The SLCA shows a closing balance of £18,500 Dr. The total of Sales Ledger customer balances is £18,830. Investigation reveals: (a) A credit sale of £200 was correctly posted to the SLCA but recorded as £250 in the customer's account. (b) Returns inwards of £80 was correctly posted to the SLCA but omitted from the customer's account. (c) A casting error in the Sales Day Book understated the total by £100.

Prepare the corrected SLCA balance and the corrected Sales Ledger total to confirm agreement.
Step-by-step solution
1. Step 1
  Decide which error affects which side. Then adjust.
Answer
Adjustments to SLCA:

(c) Casting error in Sales Day Book — SLCA was understated by £100. ↑ SLCA by £100.

Adjusted SLCA = £18,500 + £100 = £18,600 Dr

Adjustments to Sales Ledger total:

(a) Customer's account overstated by £50 (£250 − £200). ↓ Sales Ledger by £50.

(b) Customer's account missing returns of £80. ↓ Sales Ledger by £80.

Adjusted Sales Ledger total = £18,830 − £50 − £80 = £18,700

Mismatch: SLCA £18,600 vs Sales Ledger £18,700. Difference £100 — further investigation needed (another error not yet identified).
Examiner tip
Reconciliation questions are detective work. A* candidates explicitly say which side each adjustment hits, and clearly flag any residual gap requiring further work.
9Explain the purpose and benefits of control accounts
Higher• Edexcel 4AC1 style — explain (8 marks)• benefits, AO1, AO2, AO3
Question
Explain four reasons why a business prepares control accounts.
Step-by-step solution
1. Step 1
  Each reason needs definition + benefit + concrete example.
Answer
1. Detect errors in personal ledgers. If the SLCA closing balance does not equal the Sales Ledger total, an error exists in one or both — providing an early-warning system.

2. Improve internal control. Control accounts are often kept by a different person than the personal ledgers — separation of duties deters fraud and detects unauthorised entries.

3. Quick access to the total receivable/payable figure. The Trade Receivables and Trade Payables figures on the SOFP can be taken directly from the control account balances without having to add up every customer/supplier.

4. Speed up the preparation of the trial balance. The control account balance replaces dozens of individual customer/supplier balances in the TB — a major time-saver.
Examiner tip
A* answers always link each reason to a concrete OUTCOME (detection, fraud deterrence, efficiency). Generic 'they help check the books' caps at 4/8.

Key Formulae — Control accounts

The formulae you need to memorise for control accounts on the Pearson Edexcel IGCSE 4AC1 paper, with every variable defined in plain English and a note on when to use it.

SLCA closing balance
$Closing SLCA = Opening + Credit Sales − Receipts − Returns Inwards − Discount Allowed − Irrecoverable Debts ± Set-offs ± Refunds$
$Opening$
Opening Dr balance brought down
$Credit Sales$
Total of Sales Day Book for the period
$Receipts$
Cash and cheques received from customers
When to use
When reconciling the SLCA or finding a missing figure (e.g., credit sales in incomplete records).
Example
8,400 + 25,000 − 21,500 − 600 − 200 − 300 = £10,800 Dr closing balance.
PLCA closing balance
$Closing PLCA = Opening + Credit Purchases − Payments − Returns Outwards − Discount Received ± Set-offs$
$Opening$
Opening Cr balance brought down
$Credit Purchases$
Total of Purchases Day Book for the period
$Payments$
Cash and cheques paid to suppliers
When to use
Mirror of SLCA — used to reconcile PLCA with the Purchases Ledger total, or to find a missing figure.
Example
4,200 + 18,000 − 15,000 − 400 − 120 − 250 = £6,430 Cr closing balance.
Finding missing credit sales from the SLCA
$Credit Sales = Closing SLCA − Opening + Receipts + Returns Inwards + Discount Allowed + Irrecoverable Debts$
When to use
In incomplete records (Topic 4.3) where credit sales are unknown but the other movements and balances are.
Example
9,800 − 7,500 + 30,000 + 450 + 150 + 200 = £33,100 credit sales for the period.
Finding missing credit purchases from the PLCA
$Credit Purchases = Closing PLCA − Opening + Payments + Returns Outwards + Discount Received$
When to use
In incomplete records where credit purchases are the missing figure.
Example
Rearrangement of the PLCA closing formula.

Key Definitions and Keywords — Control accounts

Definitions to memorise and the exact keywords mark schemes credit for control accounts answers — sharpened from recent examiner reports for the 2026 Pearson Edexcel IGCSE 4AC1 sitting.

Control account
Examiner keyword
A summary account in the general ledger whose balance equals the total of all the individual personal account balances in the corresponding ledger. Acts as a check on the personal ledger.
Sales Ledger Control Account (SLCA)
Examiner keyword
The general ledger account whose Dr balance equals the total trade receivables — the sum of all credit customer balances in the Sales Ledger.
Purchases Ledger Control Account (PLCA)
Examiner keyword
The general ledger account whose Cr balance equals the total trade payables — the sum of all credit supplier balances in the Purchases Ledger.
Set-off (contra entry)
Examiner keyword
An entry that reduces both the SLCA and PLCA when the same party is both a customer and a supplier. Dr PLCA, Cr SLCA (or vice versa).
Refund to customer
A return of money to a customer who has overpaid. Appears on the Dr side of the SLCA (increases what the customer is owed back).
Control account reconciliation
Examiner keyword
The process of comparing the control account balance with the total of the personal ledger. Disagreements indicate errors that need investigation.

Common Mistakes and Misconceptions — Control accounts

The traps other students keep falling into on control accounts questions — taken from recent Pearson Edexcel IGCSE 4AC1 examiner reports and mark schemes — and how to avoid them.

✕Putting discount allowed on the Dr side of the SLCA.
Edexcel 4AC1 examiner reports.
Why it happens
Students associate 'discount allowed' with the income statement expense (which IS Dr).
How to avoid it
In the SLCA, discount allowed REDUCES the customer's debt → Cr. (The Dr is in the Discount Allowed expense account elsewhere.)
✕Putting returns inwards on the Dr side of the SLCA.
Why it happens
Returns inwards is Dr in the TB.
How to avoid it
In the SLCA, returns REDUCE the customer's debt → Cr.
✕Treating the control account as if it replaces the personal ledgers.
Why it happens
Misunderstanding of role.
How to avoid it
Personal ledgers (SL and PL) hold individual customer/supplier accounts. The control account is a TOTAL — it doesn't replace the detail. Both are kept.
✕Putting set-offs on the wrong side.
Why it happens
Direction confusion.
How to avoid it
Set-off reduces what each side owes. Cr SLCA (customer's debt reduced) and Dr PLCA (supplier's debt reduced) — both on the side that reduces the balance.
✕Putting irrecoverable debts on the Dr side of the SLCA.
Why it happens
Students think of it as 'the loss'.
How to avoid it
Writing off REMOVES the customer's debt → Cr SLCA. The Dr is in Irrecoverable Debts expense.
✕Putting a refund to a customer on the Cr side.
Why it happens
Students see 'money going out' and think Cr Bank Dr Customer — but for the SLCA, the customer is OWED MORE (negative debt becomes a refund obligation).
How to avoid it
A refund INCREASES what the business owes to the customer → Dr SLCA. (Bank is Cr, as usual for a payment.)

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Control accounts

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Short Study Notes — Control accounts

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What you’ll learn

How it’s examined

1State which side of the SLCA each item appears on

2State which side of the PLCA each item appears on

3Identify reasons for SLCA and Sales Ledger balance mismatch

4Calculate the closing balance of the SLCA

5Calculate the closing balance of the PLCA

6Calculate a missing credit sales figure from the SLCA

7Prepare the SLCA in T-account format

8Reconcile the SLCA with the Sales Ledger total after errors

9Explain the purpose and benefits of control accounts

SLCA closing balance

PLCA closing balance

Finding missing credit sales from the SLCA

Finding missing credit purchases from the PLCA

Control account

Sales Ledger Control Account (SLCA)

Purchases Ledger Control Account (PLCA)

Set-off (contra entry)

Refund to customer

Control account reconciliation

✕Putting discount allowed on the Dr side of the SLCA.

✕Putting returns inwards on the Dr side of the SLCA.

✕Treating the control account as if it replaces the personal ledgers.

✕Putting set-offs on the wrong side.

✕Putting irrecoverable debts on the Dr side of the SLCA.

✕Putting a refund to a customer on the Cr side.

Practice questions

Past paper style quiz

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