Overview of Computerised Accounting System Class 12: Notes and Solved Questions

What Overview of Computerised Accounting System is about

Weightage: This chapter is in Part B Option II: Computerised Accounting, which a student takes instead of Option I (Analysis of Financial Statements). Computerised Accounting carries 20 of the 80 theory marks together with Spreadsheet, Use of Spreadsheet in Business Applications and Graphs and Charts for Business Data.Source: CBSE Accountancy (055) syllabus 2026-27, Part B Option II: Computerised Accounting

In real board papers: asked in 2 of the 2 board papers we hold (2026 to 2026), on average 8 marks per paper. See the questions

Key concepts

Meaning and components of CAS

NCERT section 1.1, 1.2

CAS is the processing of accounting transactions through hardware and software to produce accounting records and reports. It takes transactions as input and produces output reports such as day books (journals), ledger, trial balance, Statement of Profit and Loss and Balance Sheet.

Five components:

• Procedure: the ordered steps followed to get a job done.
• Data: raw facts that are entered (in accounting, each transaction has four data elements: account name, account code, date and amount).
• People: the users.
• Hardware: the computer, peripherals and network.
• Software: system software and application (accounting) software.

Data vs information: data are raw facts; information is data processed for a decision. Days worked and daily rate are data; wages payable is information.

Worked example

Suppose a shop records "₹5,000, rent, 1st April, code 4301". Identify the data elements. [1 mark]

Try it first, then show the solutionSolution

1. A transaction has four data elements.
2. Amount ₹5,000; account name rent; date 1st April; account code 4301.

Answer: Amount, account name, date and account code.

Salient features of CAS

NCERT section 1.3

• Simple and integrated: sales, purchase, inventory, finance and manufacturing are linked, so one entry updates every related record.
• Transparency and control: day-to-day information is accessible, with control over who sees what.
• Accuracy and speed: user-defined templates and data-entry screens make entry fast and accurate; reports are generated instantly.
• Scalability: the system can handle more data as the business grows.
• Reliability: critical financial information is accurate, controlled and secured.

Worked example

Suppose a firm's sales double in three years and its CAS handles the extra entries without being replaced. Which feature is shown? [1 mark]

Try it first, then show the solutionSolution

1. The system grows with the business.

Answer: Scalability.

Grouping and codification of accounts

NCERT section 1.4, 1.4.1

Accounts are grouped using the accounting equation, Assets = Liabilities + Capital + (Revenues − Expenses), into the Schedule III heads (equity and liabilities, assets) plus revenues and expenses. Groups and sub-groups form a hierarchy; a code is an identification mark that keeps this hierarchy neat and makes machine processing easy.

A hierarchical account code uses the first digit for the top-level group and the next digits for sub-groups, leaving gaps for future accounts. Listing codes in ascending order then lists accounts in the right order for the statements.

Level	Code	Group
1st digit	1	Equity and liabilities
1st digit	2	Assets
1st digit	3	Revenues
1st digit	4	Expenses
2 digits	11	Shareholders' funds
2 digits	13	Non-current liabilities
2 digits	14	Current liabilities
2 digits	21	Non-current assets
2 digits	23	Current assets

Worked example

Using the scheme above, which group does code 2305 belong to, and why are codes like 12 left unused? [2 marks]

Try it first, then show the solutionSolution

1. First digit 2 = assets; first two digits 23 = current assets.
2. Gaps (such as 12) give flexibility to insert new groups later without recoding.

Answer: 2305 is a current asset account; the gap allows future expansion.

Types of codes and designing a coding structure

NCERT section 1.4.1.1-1.4.1.3, 1.4.2

• Sequential codes: numbers or letters in consecutive order, used mainly for source documents such as cheques and invoices (CL001, CL002 ...). They help trace documents and spot missing numbers.
• Block codes: a range of numbers split into sub-ranges, each for a group (100-199 small pumps, 200-299 medium pumps ...). Within a block, numbers are usually sequential.
• Mnemonic codes: letters or abbreviations that are easy to remember (SJ for sales journal, NDLS for New Delhi railway station).

To design a coding structure: identify the hierarchy (for example trust → school → year → stream → class → section → student), decide which levels need codes, then give each level enough digits for its maximum size (99 schools need 2 digits; 9 sections need 1 digit).

Worked example

Suppose a chain has up to 40 stores, each with up to 8 departments and up to 500 products per department. Design a coding structure and code product 37 in department 5 of store 12. [3 marks]

Try it first, then show the solutionSolution

1. Stores up to 40: 2 digits. Departments up to 8: 1 digit. Products up to 500: 3 digits.
2. Structure: SS D PPP (6 digits).
3. Store 12, department 5, product 37 → 12 5 037.

Answer: Code 125037.

Types of accounting software packages

NCERT section CBSE syllabus: software packages (generic, specific, tailored)

Accounting software comes in three broad types, compared below. The choice depends on the size of the business, how unusual its needs are, cost, flexibility, the training required and how secure the data must be.

Basis	Ready-to-use (generic)	Customised (specific)	Tailored
Who it suits	Small businesses with standard needs	Medium businesses with some special needs	Large organisations with complex, unique needs
Cost	Lowest	Moderate	Highest
Flexibility	Little; used as supplied	Standard package adapted to the user	Built specially for the user
Training and support	Minimal training; easy to install	More training needed	Specialised training; developer support
Data security	Lower	Better	High

Worked example

Suppose a small stationery shop with standard accounting needs and a limited budget wants accounting software. Which type suits it and why? [3 marks]

Try it first, then show the solutionSolution

1. Its needs are standard and the business is small.
2. Ready-to-use software is cheap, easy to install and needs little training.
3. Its limited flexibility does not matter for standard needs.

Answer: Ready-to-use (generic) software.

Using CAS: activities, vouchers and entries

NCERT section 1.5

One-time activities: creating the company (organisation details, accounting year), creating account groups and ledgers with their codes (the master files), setting opening balances and users.

Recurring activities: entering transactions through vouchers and generating reports (day books, ledgers, trial balance, Statement of Profit and Loss, Balance Sheet, cash flow statement).

Voucher	Used for	Example
Receipt voucher	Money received in cash or bank	Cash received from a debtor
Payment voucher	Money paid in cash or by bank	Rent paid by cheque
Contra voucher	Transfers between cash and bank accounts only	Cash deposited into bank; cash withdrawn from bank
Sales voucher	Sales of goods (cash or credit)	Goods sold on credit to Mehta Stores
Purchase voucher	Purchases of goods (cash or credit)	Goods bought on credit from Singh Traders
Journal voucher	Non-cash adjustments	Depreciation, outstanding expenses, transfers

Data entry is checked by validation (the software refuses wrong types or values, such as a date in an amount field) and verification (checking entries against source documents). Adjusting entries (outstanding and prepaid items, depreciation) are passed through journal vouchers; the software then transfers nominal accounts to the Statement of Profit and Loss (closing) and carries balances forward to the next year (opening). A post-dated voucher is entered now but affects the books only on its later date.

Worked example

Which voucher is used for: (i) cash withdrawn from bank for office use, (ii) depreciation on machinery, (iii) cheque received from a customer? [3 marks]

Try it first, then show the solutionSolution

1. (i) Movement between cash and bank: contra voucher.
2. (ii) Non-cash adjustment: journal voucher.
3. (iii) Money received: receipt voucher.

Answer: (i) Contra; (ii) journal; (iii) receipt.

Security features of CAS

NCERT section 1.5 (security features)

• Password security: a password is the key to access the system. User rights can be set by policy, so a user may see one set of data and be denied another.
• Data audit: records who changed what in the original data, fixing responsibility and protecting data integrity (similar to an audit trail).
• Data vault: extra security through encryption, which scrambles data so that it cannot be read even if it reaches the wrong hands.

Worked example

Suppose a cashier altered a sales entry, and the owner wants to know who changed it and when. Which security feature helps? [1 mark]

Try it first, then show the solutionSolution

1. The feature records changes to the original data and the user who made them.

Answer: Data audit.

Advantages, limitations and accounting information sub-systems

NCERT section 1.6, 1.7, 1.8

Advantages: timely reports in the desired format; efficient record keeping; effective control; economy in processing; confidentiality of data (also speed and arithmetic accuracy).

Limitations: fast obsolescence of technology needs fresh investment; data can be lost or corrupted by power failures or disk damage; data are exposed to hacking and viruses; reports that were not programmed cannot be generated.

Accounting Information System (AIS) sub-systems: cash and bank; sales and accounts receivable; inventory; purchase and accounts payable; payroll; fixed assets; expense; tax; final accounts; costing; budget; and management information system (MIS).

Worked example

Suppose a sudden power cut during data entry corrupts a day's records. Which limitation is this, and what precaution reduces it? [3 marks]

Try it first, then show the solutionSolution

1. Data may be lost or corrupted due to power interruptions.
2. Regular backups and an uninterrupted power supply reduce the risk.

Answer: Loss of data through power interruption; reduce it with backups and power backup.

Overview of Computerised Accounting System in real life

Each concept, met in an everyday situation. Read the situation, answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Topics in this chapter

• Features, Advantages and Limitations of CAS
• Accounting Vouchers in Computerised Accounting
• Security Features of Computerised Accounting

Overview of Computerised Accounting System: key facts

Accounting equation used for grouping

Assets = Liabilities + Capital + (Revenues − Expenses)

Digits needed for a coding level

1. 1.Smallest number of digits whose largest value covers the maximum count (up to 9
2. 2.1 digit; up to 99
3. 3.2 digits; up to 999
4. 4.3 digits)

Hierarchical code

Group digit(s) + sub-group digit(s) + account digits, e.g. 2 (assets) 3 (current) 05 (account) = 2305

Components of CAS

Procedure + Data + People + Hardware + Software

How the board asks Overview of Computerised Accounting System

The question patterns to expect, and the method that works for each.

Tricks to remember Overview of Computerised Accounting System

Short memory aids. Say each one aloud once, then use it on a question the same day.

• PD-PHS

  Procedure, Data, People, Hardware, Software.

  Use it when: Components of CAS.

• STARS

  Simple and integrated, Transparency, Accuracy and speed, Reliability, Scalability.

  Use it when: Features of CAS.

• Sequence, Block, Mnemonic

  Running number, range per group, memory letters.

  Use it when: Types of codes.

• PAV for security

  Password, Audit, Vault.

  Use it when: Security features.

Overview of Computerised Accounting System: board-level solved questions

Ordered from board level to HOTS. Cover the solution, write your own, then compare step by step.

Case-study practice (Section E style)

Read the situation, then answer every part. In the board paper this is a 4-mark question split into 1 + 1 + 2 marks.

Where the marks are

How a typical answer is split into step marks. Show every step: a right final answer alone rarely earns full marks.

Where students lose marks in Overview of Computerised Accounting System

The slips examiners see most often, and what to write instead.

• ✗Mistake: Listing "ledger" or "reports" as a component of CAS

  Mixing outputs with components.

  ✓Do this: Components: procedure, data, people, hardware, software.

  Usually costs: 1 mark.

• ✗Mistake: Confusing block and sequential codes

  Both use numbers.

  ✓Do this: Sequential: one running series. Block: ranges set aside for groups.

  Usually costs: 1 mark.

• ✗Mistake: Using a receipt or payment voucher for cash-bank transfers

  Money moves.

  ✓Do this: Transfers between cash and bank use a contra voucher.

  Usually costs: 1 mark.

• ✗Mistake: Giving too few digits to a coding level

  Not checking the maximum count.

  ✓Do this: Choose digits from the maximum possible number at that level (up to 99 needs 2).

  Usually costs: 1 mark.

• ✗Mistake: Calling data audit "data vault"

  Similar names.

  ✓Do this: Audit traces changes; vault encrypts data.

  Usually costs: 1 mark.

NCERT exercise guide: Overview of Computerised Accounting System

What each exercise in the NCERT chapter tests, how to approach it, and a question of the same kind solved step by step. Questions here are written in our own words.

Overview of Computerised Accounting System: previous year questions

• Asked in 2 of the 2 board papers we hold (2026 to 2026), on average 8 marks per paper; 7 questions in all, counting OR alternatives. In 4 of 4 sample papers.

Counted from the real papers on our previous year papers page, not estimated. Average marks are over every board paper we hold, with an OR pair counted once. Chapter tags are ours.

Solved board questions from Overview of Computerised Accounting System

Real questions from recent papers. Try each one first, then open our step-by-step solution with marks per step.

Every Overview of Computerised Accounting System question, by year

Practice questions on Overview of Computerised Accounting System

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

1. Q1 · 1 mark · MCQBoard level

   Which code type uses abbreviations like SJ for sales journal?
   (a) sequential
   (b) block
   (c) mnemonic
   (d) hierarchical

   Hint

   Memory aid.

   Answer

   (c) mnemonic

2. Q2 · 1 mark · MCQBoard level

   A sequential code is mainly applied to:
   (a) source documents such as cheques and invoices
   (b) groups of products
   (c) passwords
   (d) reports

   Hint

   Consecutive numbers.

   Answer

   (a)

3. Q3 · 3 marks · Short answerBoard level

   State any three limitations of a computerised accounting system.

   Hint

   Obsolescence, data loss, hacking.

   Answer

   Fast obsolescence of technology; loss or corruption of data due to power failure; exposure to hacking and viruses (also: unprogrammed reports cannot be generated).

4. Q4 · 3 marks · Short answerBoard level

   State any three advantages of CAS.

   Hint

   Speed and control.

   Answer

   Timely reports in the desired format; efficient record keeping; effective control (also economy and confidentiality).

5. Q5 · 3 marks · Short answerHarder board level

   Explain contra voucher, receipt voucher and post-dated voucher with an example each.

   Hint

   Movement, inflow, future date.

   Answer

   Contra: transfers between cash and bank (cash withdrawn from bank). Receipt: money received (cash from a debtor). Post-dated: entered now for a future date and affects the books only on that date (a cheque dated next month).

6. Q6 · 3 marks · Short answerHarder board level

   Suppose a company has up to 9 regions, up to 60 branches per region and up to 900 customers per branch. Design a coding structure and code customer 45 of branch 7 in region 3.

   Hint

   Digits for 9, 60 and 900.

   Answer

   Region 1 digit, branch 2 digits, customer 3 digits: R BB CCC. Code: 3 07 045 = 307045.

7. Q7 · 4 marks · Short answerHarder board level

   Compare ready-to-use, customised and tailored software on cost, flexibility and training.

   Hint

   Low to high.

   Answer

   Cost: low, moderate, high. Flexibility: little, adapted, built to need. Training: minimal, more, specialised.

8. Q8 · 4 marks · Short answerHOTS / competency

   Suppose an employee misuses another's password and changes the cash book. Which two security features would help detect and prevent this, and how?

   Hint

   Audit and rights.

   Answer

   Data audit records which login changed which entry and when, helping detect it. Password security with strict user rights (and changing passwords regularly) limits who can alter the cash book.

9. Q9 · 1 mark · Assertion-reasonHOTS / competency

   Assertion (A): Gaps are left in the second digit of account codes (such as 11, 13, 14).
   Reason (R): Gaps allow new groups to be added later without disturbing existing codes.
   (a) Both true and R explains A (b) Both true, R does not explain A (c) A true, R false (d) A false, R true

   Hint

   Flexibility.

   Answer

   (a)

10. Q10 · 3 marks · Short answerHarder board level

    Name any four sub-systems of an accounting information system and state what one of them reports.

    Hint

    Cash, sales, inventory, payroll...

    Answer

    For example: cash and bank; sales and accounts receivable; inventory; payroll. The sales and accounts receivable sub-system reports sales, collections, overdue accounts and an ageing schedule of debtors.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1. 1.What are the four data elements of a transaction?Show answer

   Account name, account code, date and amount.

2. 2.What does scalability mean in CAS?Show answer

   The system can handle more data as the business grows.

3. 3.Give an example of a mnemonic code.Show answer

   SJ for sales journal; NDLS for New Delhi.

4. 4.Which voucher records depreciation?Show answer

   Journal voucher.

5. 5.What does data audit do?Show answer

   Records who changed what in the data, like an audit trail.

6. 6.Name two limitations of CAS.Show answer

   Fast obsolescence; data loss from power failure (also hacking, unprogrammed reports).

7. 7.What is a post-dated voucher?Show answer

   A voucher entered now that affects the books on a future date.

8. 8.Which software type suits a large organisation with unique needs?Show answer

   Tailored software.

Quick revision checklist

The night before the exam: can you do each of these without looking?

• ☐Can you name the five components of CAS?
• ☐Can you explain the five features?
• ☐Can you build a hierarchical account code?
• ☐Can you distinguish sequential, block and mnemonic codes?
• ☐Can you design a coding structure from a hierarchy?
• ☐Can you compare ready-to-use, customised and tailored software?
• ☐Can you pick the right voucher for a transaction?
• ☐Can you explain password security, data audit and data vault?
• ☐Can you list advantages and limitations?
• ☐Can you name AIS sub-systems?

Overview of Computerised Accounting System: frequently asked questions