ACC2231 – Errors Which do not Affect the Trial Balance

Accounting errors that do not affect the trial balance fall into one of six categories as follows:

  1. Error of Principle
  2. Errors of Omission
  3. Error of Commission
  4. Compensating Error
  5. Error of Original Entry
  6. Complete Reversal of Entries

Error of Principle

An error of principle in accounting occurs when the bookkeeping entry is made to the wrong type of account. For example, if a 1,000 spent on motor vehicle maintenance is debited to the motor vehicle account instead of the asset account;

The error was,
Dr Cr
Motor vehicle 1,000
Cash/Bank 1,000
Should be,
Dr Cr
Motor vehicle maintenance 1,000
Cash/Bank 1,000
Correcting entries
Dr Cr
Motor vehicle maintenance 1,000
Motor vehicle 1,000

Error of Omission

Errors of omission occur when a bookkeeping entry has been completely omitted from the accounting records.

Example, the payment 4,000 from a debtor has been omitted in both books.

The error was,
Dr Cr
– no transaction at all  nil
– no transaction at all  nil
Should be,
Dr Cr
Cash/Bank 4,000
Debtor 4,000
Correcting entries
Dr Cr
Cash/Bank 4,000
Debtor 4,000

Error of Commission

Error of commission occurs when an item is entered to the correct type of account but the wrong account. For example is cash received of 2,000 from Nur is credited to the account of Nor.

The error was,
Dr Cr
Cash/Bank 2,000
Nor 2,000
Should be,
Dr Cr
Cash/Bank 2,000
Nur 2,000
Correcting entries
Dr Cr
Nor 2,000
Nur 2,000

Compensating Error

A compensating error occurs when two or more errors cancel each other out. For example, if the fixed assets account is incorrectly totalled and understated by 600, and the wages account is also incorrectly totalled and overstated by 600, then the posting to correct the error would be as follows:

Correcting entries
Dr Cr
Fixed Assets 600
Wages 600

Error of Original Entry

An error of original entry occurs when an incorrect amount is posted to the correct accounts.

A particular example of an error of original entry is a transposition error where the numbers are not entered in the correct order. For example, if cash paid to a supplier of 2,140 was posted as 2,410 then the correcting entry of 270 would be.

A good indicator for a transposition error is that the difference (in this case 270) is divisible by 9.

The error was,    
  Dr Cr
Accounts payable 2,410
Cash/Bank 2,410
Should be,
Dr Cr
Accounts payable 2,140
Cash/Bank 2,140
Correcting entries
Dr Cr
Cash/Bank 270
Accounts payable 270

Complete Reversal of Entries

Complete reversal of entries errors occur when the correct amount is posted to the correct accounts but the debits and credits have been reversed. For example if a cash sale is made for 400 and posted incorrectly as follows:

Accounting Errors – Incorrect posting
Account Debit Credit
Sales 400
Cash 400

As you can see, by right, the nature for sales account should always be at the credit side. Same goes to the cash account. When we made a cash sale, the cash receive will increase the the cash account (asset account). Then the rule is debit the cash account.

Then to correct the accounting error the original entry must be reversed and the correct entry made, this can be achieved by doubling the original amounts as follows:

Accounting Errors – Complete Reversal of Entries
Account Debit Credit
Sales 800
Cash 800

Why it is 800? Actually there are two transaction of 400 we have to make. The first transaction is to ‘zerorize’ both account. Taking out 400 from the sales by debiting the sales account and another 400 from the cash account by debiting the amount to cancel the originally entered figure.

The second transaction, is to record the normal transaction because all the said accounts are now at ‘zero’ state. You can see that when the second transaction is done, there were 2 same transaction just to correct the errors. The amount now is double!


The type of accounting errors that do not affect the trial balance are summarized in the table below.

Summary of Accounting Error Types
Accounting Errors Description
Error of Principle in Accounting Correct amount, wrong type of account
Errors of Omission in Accounting Entry missed from accounting records
Error of Commission Correct amount and type of account but wrong account
Compensating Error Two or more errors balance each other out
Error of Original Entry Correct accounts, wrong amounts
Complete Reversal of Entries Correct amount and account, entries reversed

Where possible all accounting errors should be identified and corrected, if the accounting errors are immaterial to the accounts then, as a last resort, the balance could be carried in the balance sheet on a suspense account or written off to the income statement as a sundry expense.

ACC2232 – Inventory Control and Valuation

In order for the organization to stay competitive, the inventory control and valuation is important. An inventory valuation allows a company to provide a monetary value for items that make up their inventory. Inventories are usually the largest current asset of a business, and proper measurement of them is necessary to assure accurate financial statements. If inventory is not properly measured, expenses and revenues cannot be properly matched and a company could make poor business decisions.

For your benefits, let’s watch some short videos regarding the valuation of inventory.

The two most widely used inventory accounting systems are the periodic and the perpetual.

  • Perpetual: The perpetual inventory system requires accounting records to show the amount of inventory on hand at all times. It maintains a separate account in the subsidiary ledger for each good in stock, and the account is updated each time a quantity is added or taken out.
  • Periodic: In the periodic inventory system, sales are recorded as they occur but the inventory is not updated. A physical inventory must be taken at the end of the year to determine the cost of goods

Regardless of what inventory accounting system is used, it is good practice to perform a physical inventory at least once a year.


  • No material are purchased and no product are manufactured until they are needed
  • To reduce or eliminate inventories at every stage of production
  • Minimize storage cost

FIFO (First In First Out)

  • First material in will be the first material issued
  • Most logical method and accepted by IRB
  • Lower cost, higher profit

LIFO (Last In First Out)

  • Most recent material received, will be the first to be issued
  • Not really logical and not accepted by IRB
  • Higher cost, lower profit


  • Material issued is valued at average cost price
  • Accepted by IRB
Weighted Average  = Total Cost of Inventory
Unit Cost Total Units in Inventory

Like FIFO and LIFO methods, AVCO is also applied differently in periodic inventory system and perpetual inventory system. In periodic inventory system, weighted average cost per unit is calculated for the entire class of inventory. It is then multiplied with number of units sold and number of units in ending inventory to arrive at cost of goods sold and value of ending inventory respectively. In perpetual inventory system, we have to calculate the weighted average cost per unit before each sale transaction.

There are so many videos you can find in the YouTube. Varies in minutes duration but why not? Just spend a couple of minutes to understand various presentations. Who knows, you might get addicted! Hahaha

I also uploaded the a calculation sheet to calculate the FIFO, LIFO and WACO. If possible try to download this, make 3 copies and we will use them in class.

Download this… Store Ledger Card

Example – FIFO

Use the following information to calculate the value of inventory on hand on Mar 31 and cost of goods sold during March in FIFO periodic inventory system and under FIFO perpetual inventory system.

Mar 1 Beginning Inventory 68 units @ $15.00 per unit
5 Purchase 140 units @ $15.50 per unit
9 Sale 94 units @ $19.00 per unit
11 Purchase 40 units @ $16.00 per unit
16 Purchase 78 units @ $16.50 per unit
20 Sale 116 units @ $19.50 per unit
29 Sale 62 units @ $21.00 per unit

Example – LIFO

Use LIFO on the following information to calculate the value of ending inventory and the cost of goods sold of March.

Mar 1 Beginning Inventory 60 units @ $15.00
5 Purchase 140 units @ $15.50
14 Sale 190 units @ $19.00
27 Purchase 70 units @ $16.00
29 Sale 30 units @ $19.50

Example – AVCo

Apply AVCO method of inventory valuation on the following information, first in periodic inventory system and then in perpetual inventory system to determine the value of inventory on hand on Mar 31 and cost of goods sold during March.

Mar 1 Beginning Inventory 60 units @ $15.00 per unit
5 Purchase 140 units @ $15.50 per unit
14 Sale 190 units @ $19.00 per unit
27 Purchase 70 units @ $16.00 per unit
29 Sale 30 units @ $19.50 per unit


ACC 2232 – Economic Order Quantity (EOQ)

What is EOQ?

EOQ is the acronym for economic order quantity. The economic order quantity is the optimum quantity of goods to be purchased at one time in order to minimize the annual total costs of ordering and carrying or holding items in inventory.

EOQ is also referred to as the optimum lot size.

The formula to calculate the economic order quantity is the square root of [(2 times the annual demand in units times the incremental cost to process an order) divided by (the incremental annual cost per unit to carry an item in inventory)].


  •  Interest on fund borrowed
  •  Storage charges (rent)
  •  Insurance and security
  •  Cost of obsolescence of stocks


  •  Clerical costs preparing purchase order and transportation


  •  Cost without having stock
  •  Loss of contribution
  •  Loss of customer future sale/goodwill
  •  Production stoppage
Let’s try this!
Annual demand quantity : 1500 units
Ordering cost: RM30 per order
Cost per unit of item: RM5
Holding cost: 20% of inventory cost
Calculate the EOQ.
Another one…
Nadzmi runs a mail-order business for gym equipment. Annual demand for the AbsFlexer is 16,000. The annual holding cost per unit is $2.50 and the cost to place an order is $50. What is the economic order quantity?
However, the EOQ implementation has to be based on the following assumptions….

  • Demand is constant
  • Holding and ordering cost are constant
  • Unit price is constant
  • Quick delivery
  • Replenishment is made instantaneously (the whole batch is delivered at once)

ACC 2232 – Answers to Classification of Costs

Well, as promised, below are the answers for relevant and irrelevant cost…

Solution – Relevant and irrelevant costs

We have two alternatives: (a) dental care division is sold off and (b) dental care division continues to operate. Identifying relevant costs and irrelevant costs is easy when we see if a cost changes between two alternatives or not. If it changes it is relevant, if it doesn’t it is irrelevant.

  1. CEO’s salary is irrelevant because it shall remain the same whether the dental care division exists or it is disposed off.
  2. Salaries of employees who can be laid off is relevant because the cost shall continue to be incurred if the division exists but it shall be reduced to zero if the division is disposed off.
  3. Salaries of employees who can’t be laid-off is irrelevant because it shall continue to be incurred regardless of whether the division is disposed off or not.
  4. One-time retirement benefits cost is relevant because it shall be incurred only if the division is disposed off. If the division continues to operate, the cost shall continue to be incurred.
  5. Cost of raw materials is relevant cost because it shall be zero if the division no longer operates because then there will be no production.
  6. Annual directors fee is irrelevant cost because it shall stay the same even if dental care is disposed off.
  7. Interest paid on dental care division loans is relevant because if the division is sold off the loan could be paid off which shall cease the interest cost.
  8. Salary of the dental care chief operating officer is relevant because he will most likely lose his job. If he is accommodated in another division, this cost shall be irrelevant.
  9. Company-wide quality certification fee is irrelevant because it shall continue to be incurred even if dental care division is no longer there.
  10. License fee paid for manufacturing dental care products is a relevant cost because it shall cease with disposal of the division.
  11. Head office rent is irrelevant because it shall remain the same regardless of the number of divisions. If a division is sold-off, head-office will still exist and the office rent shall be incurred.
  12. Audit fee is irrelevant if it does not depend on the number of divisions. Audit shall be conducted even if there is one division less.



Solution – Controllable and Uncontrollable Costs

The controllable costs are: direct materials, direct labor, indirect materials, and indirect labor (supervision). Depreciation, insurance, allocated repairs and maintenance, and allocated rent and utilities expense are not under the influence of the production manager. Under responsibility accounting, managers are evaluated based on costs that they can control. Hence, uncontrollable costs are ignored in evaluating managers.

ACC1231 & BUS1233 Accounting Equation and Business Transactions Exercises

So far, there are no questions from you guys, so I assume that all of you understood. Attached is the word documents containing simple accounting exercises. I hope you manage to do them and if you do them on by yourself without discussion, it is even better!  Potential marks ♥♥♥♥

Accounting Equation and Business Transactions

start cracking your heads and you have 6 days to finish them