Simplification & Approximation: Your Fastest Marks in Bank Prelims

A friendly, exam-ready guide to Simplification and Approximation for IBPS and SBI bank prelims. Master the BODMAS order, smart rounding, and the fraction tricks that turn tricky-looking sums into 30-second free marks — with worked examples throughout.

By the PadhoDost Team · 📖 7 min read · Updated 4 August 2026

Part of Banking (IBPS / SBI) prep

🧠 The billing counter rule

Picture a busy Big Bazaar checkout. The cashier does not add prices in random order — she first scans the items inside your basket, then multiplies each by its quantity, and only at the very end adds and subtracts to give you the final bill. Maths follows the exact same discipline. Do the steps out of order and, just like a wrong bill, your answer goes wrong. That fixed order has a name: BODMAS.

What these questions really test

In bank prelims (IBPS & SBI, PO & Clerk), Simplification asks for the exact value, while Approximation asks for the nearest value — you round the messy decimals first, then solve. Both are pure speed-and-accuracy questions. Around 5 to 10 marks sit here, and a strong aspirant clears each one in 20 to 30 seconds. With roughly 20 minutes for the whole Quant section and 0.25 negative marking, these are your must-get, must-get-fast marks — the ones that free up time for Data Interpretation later.

BODMAS: the order that never changes

BODMAS = Brackets → Orders (powers & roots) → Division → Multiplication → Addition → Subtraction. Key point: Division and Multiplication are EQUAL in rank — do them left to right. Addition and Subtraction are also equal — again, left to right. Inside brackets, open ( ) first, then { }, then [ ].

📝 Worked example — exact simplification

Solve: 8 × (12 − 4) ÷ 4 + 3² − 5

Step 1 — Brackets: (12 − 4) = 8, giving 8 × 8 ÷ 4 + 3² − 5

Step 2 — Orders: 3² = 9, giving 8 × 8 ÷ 4 + 9 − 5

Step 3 — Multiply/Divide, left to right: 8 × 8 = 64, then 64 ÷ 4 = 16, giving 16 + 9 − 5

Step 4 — Add/Subtract, left to right: 16 + 9 = 25, then 25 − 5 = 20

Answer = 20

⚠️ The classic trap is doing addition before multiplication. 2 + 3 × 4 is NOT 20 — multiplication comes first, so 3 × 4 = 12, then 2 + 12 = 14. In the exam, one out-of-order step turns a sure mark into −0.25. Lock the BODMAS sequence in your head before you touch the numbers.

Approximation: round smart, save seconds

How to approximate in under 30 seconds

  1. 1Round each messy number to the nearest easy one: 649.8 → 650, 24.03 → 24, 8.97% → 9%.
  2. 2Turn awkward percentages into friendly fractions: 33.33% = 1/3, 12.5% = 1/8, 16.67% = 1/6.
  3. 3For square roots, find the two whole numbers it sits between: √150 lies between 12 (144) and 13 (169), so ≈ 12.2.
  4. 4Apply BODMAS on the rounded numbers — the order rule still holds even in approximation.
  5. 5Pick the closest option. Answer choices are spaced far apart, so a tiny rounding gap never changes your choice.

📝 Worked example — approximation

Approximate: 1249.96 ÷ 24.98 + 15.02% of 799.9 = ?

Round: 1249.96 → 1250, 24.98 → 25, 15.02% → 15%, 799.9 → 800

Division first (BODMAS): 1250 ÷ 25 = 50

Percentage: 15% of 800 = (15/100) × 800 = 120

Add: 50 + 120 = 170

Answer ≈ 170

Fraction%Fraction%
1/2501/812.5
1/333.331/911.11
1/4251/1010
1/5201/119.09
1/616.671/128.33
1/714.291/156.67
💡 Memorise the fraction–percentage table above, plus squares up to 30 and cubes up to 15. When you instantly 'see' 37.5% as 3/8, or recognise 576 as 24², approximation stops being calculation and becomes recognition — and that is exactly how toppers clear 35 questions while others are still multiplying.

Quick revision

  • ✓BODMAS order is fixed: Brackets, Orders, Division/Multiplication (left to right), Addition/Subtraction (left to right).
  • ✓Simplification = exact value; Approximation = nearest value after rounding.
  • ✓Round first, then apply BODMAS — never the other way round.
  • ✓Convert tough percentages into fractions to multiply faster.
  • ✓Aim for 20–30 seconds per question; with −0.25 marking, skip the odd tricky one instead of guessing blindly.

⚡ Quick check

Approximate the value: 24.97% of 480.12 + 18.03 × 4.96 = ?

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