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TNPSC simplification practice questions: BODMAS, decimals and fractions

By the PrepMatic team · Updated 9 Oct 2026 · 3 min read

Simplification is the first item in the Group 4 aptitude syllabus for a reason: it is the arithmetic skill that every other topic rests on. If you can evaluate an expression quickly and correctly, you spend less time on interest, percentage and mensuration. TNPSC's questions are direct, with no tricks except the order of operations and the occasional shortcut. The five questions below show both. TNPSC aptitude and mental ability sets this topic in the context of the whole subject.

What this topic covers

• Order of operations (BODMAS): brackets, orders (powers and roots), division, multiplication, addition and subtraction.
• Fractions and decimals: converting between them and combining them.
• Powers and roots: squares, cubes, square roots and the identities that shorten them.
• Mental shortcuts: differences of squares, multiplying near 100 and fraction-to-decimal equivalents.

Sample questions

Question 1

Find the value of 15 + 3 × 4 − 6 ÷ 2.

• A. 33
• B. 24
• C. 21
• D. 12

Question 2

Find the value of (25 + 15) ÷ 8 × 3.

• A. 5
• B. 5/3
• C. 120
• D. 15

Question 3

Find the value of 0.6 × 0.5 + 2.7 ÷ 0.9.

• A. 3.0
• B. 3.33
• C. 3.3
• D. 3.03

Question 4

Find the value of 3/4 + 5/6 − 1/3.

• A. 5/4
• B. 7/6
• C. 9/12
• D. 3/2

Question 5

Find the value of 96 × 104.

• A. 9,996
• B. 9,984
• C. 10,016
• D. 9,904

Answers and explanations

1. B. Multiply and divide first: 3 × 4 = 12 and 6 ÷ 2 = 3. Then 15 + 12 − 3 = 24. Working strictly left to right gives 33, which is the trap.
2. D. The bracket gives 40. Then 40 ÷ 8 = 5, and 5 × 3 = 15. Division and multiplication have equal rank, so go left to right. Option B, 5/3, results from dividing by 8 × 3, which is a common slip.
3. C. 0.6 × 0.5 = 0.3 and 2.7 ÷ 0.9 = 3. The sum is 3.3.
4. A. The common denominator is 12: 9/12 + 10/12 − 4/12 = 15/12 = 5/4.
5. B. 96 × 104 = (100 − 4)(100 + 4) = 100² − 4² = 10,000 − 16 = 9,984.

How to prepare simplification

Spend the first week on tables and tricks, not on questions. Know squares up to 30, cubes up to 15, and the decimal equivalents of 1/2 through 1/16. These let you convert, compare and cancel without writing. Write them on a card and test yourself for ten minutes a day.

Then practise "approximate or exact" decisions. When the options are far apart (as in 24, 33, 21, 12), you only need an estimate, and doing a rough calculation first can save you 20 seconds. When the options are close together (as in question 3), compute exactly.

Group your errors. If you lose marks on order of operations, redo ten BODMAS expressions. If you lose them on decimals, shift the decimal point before you divide, so that 2.7 ÷ 0.9 becomes 27 ÷ 9. A short error log with two columns, "what I did" and "what I should do", is more useful than another hundred questions.

The same fluency helps in TNPSC percentage practice and TNPSC simple and compound interest practice. For number patterns that are not arithmetic, see TNPSC number series practice.

Take the full topic test on PrepMatic

Speed is the point of simplification, and a stopwatch is the best way to build it. PrepMatic topic tests are timed (about 15 questions, 30 minutes), and your analytics show speed per question, so you can see whether you are getting faster. The study plan can also schedule short aptitude sessions around your daily hours, which suits an early-morning routine.

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