Approximation Questions for IBPS RRB Exam, Solved Problems

Approximation is a mathematical technique used to simplify complex calculations by finding values that are close to the exact numbers. This technique is especially useful in competitive exams like banking exams, where time is limited and quick calculations are essential.  

Approximation Questions include operations like addition, subtraction, multiplication, division, percentages, squares, square roots, and sometimes involve BODMAS (order of operations).

Approximation Questions in IBPS RRB Exam

Approximation questions are a key part of the Quantitative Aptitude section in the IBPS RRB exam for Probationary Officer and Clerk Posts, designed to test a candidate’s ability to quickly estimate numerical values to save time during the exam. These questions typically involve rounding off numbers and performing simplified arithmetic operations such as addition, subtraction, multiplication, division, percentages, and square roots to arrive at an approximate answer rather than an exact one.

Importance of Approximation in Banking Exams

1. Time Efficiency: Approximations allow you to solve problems faster by simplifying calculations. This is important in bank exams where time management is a significant factor.

2. Simplifying Complex Calculations: It helps in breaking down complex arithmetic operations into more manageable steps.

Checking Reasonableness of Answers: Approximation can be used to quickly verify if an answer is reasonable, which is useful for multiple-choice questions.

Approximation Questions Tricks

1. Rounding Off Numbers:

• Round off numbers to the nearest ten, hundred, or thousand to simplify addition, subtraction, multiplication, and division.

• For example, rounding 498 to 500 or 1523 to 1500.

2. Using Significant Figures:

• Retain a few significant digits and drop less significant ones to simplify calculations.

• For example, approximating 123.456 to 123.5 or 0.004567 to 0.00457.

3. Multiplication and Division by Powers of 10:

• Simplify calculations by multiplying or dividing by powers of 10.

• For example, 423 × 99 can be approximated as 423 × 100 = 42300 and then subtract 423 (42300 - 423 = 41877).

4. Using Common Fractions:

• Convert complex fractions into simpler ones.

• For example, instead of using 0.3333, use 1/3, or instead of 0.142857, use 1/7.

Weightage of Approximation Questions

1. You can expect 5 to 10 approximation questions in every bank exam especially in the prelims phase.

2. These questions are quite easy to solve if you have practiced well on your calculation speed.

3. You can solve all the questions within 3 to 4 minutes with 100% accuracy.

4. These questions can increase your chances of clearing the exam.

Approximation Solved Examples

1. Addition/Subtraction:

Approximate 674 + 289. Round off to 670 + 290 = 960.

2. Multiplication:

Approximate 47 × 19. Round off to 50 × 20 = 1000.

3. Division:

Approximate 635 ÷ 48. Round off to 640 ÷ 50 = 12.8.

4. Percentage Calculations:

Calculate 32% of 249. Round off 32% to 30% and 249 to 250, giving 30% of 250 = 75.

BODMAS Rule in Approximation

The BODMAS rule (Brackets, Orders, Division and Multiplication, Addition and Subtraction) is essential for solving mathematical expressions accurately. When applying the BODMAS rule in approximation, the goal is to simplify complex expressions while still adhering to the correct order of operations. Here’s how you can apply the BODMAS rule effectively in approximation:

BODMAS Rule Overview

• Brackets: Simplify expressions inside brackets first.

• Orders: Handle exponents and roots next.

• Division and Multiplication: Proceed from left to right.

• Addition and Subtraction: Proceed from left to right.

Applying BODMAS in Approximation

1. Simplify Within Brackets:

• Approximate values inside brackets first.

• Example: For (49.6+52.3), approximate as (50+50)=100.

2. Handle Orders (Exponents and Roots):

• Approximate values before applying exponents or roots.

• Example: 5.1252=25

3. Perform Division and Multiplication:

• Approximate numbers before dividing or multiplying, if possible.

• Example: 49.8×19.2 ≈ 50×20 = 1000

4. Perform Addition and Subtraction:

• Approximate numbers before adding or subtracting.

• Example: 674.3+289.6 ≈ 670+290 = 960

Approximation Solved Questions

Q1. Simplify (49.8+50.4)÷4.2

1. Brackets: Approximate 49.8+50.4 ≈ 50+50=100

2. Division: Approximate 100÷4.2 ≈ 100÷4 = 25

Q2. Simplify 15.3+8.7×(3.2+1.8)

1. Brackets: Approximate 3.2+1.8 ≈ 5

2. Multiplication: Approximate 8.7×5 ≈ 9×5 = 45

3. Addition: Approximate 15.3+45 ≈ 15+45 = 60

Simplify (98.7−45.6)×2.3(98.7 - 45.6) \times 2.3(98.7−45.6)×2.3

1. Brackets: Approximate 98.7−45.6 ≈ 100−45 = 55

2. Multiplication: Approximate 55×2.3 ≈ 55×2 = 110

Previous Year Asked Approximation Questions

Ques 1: Approximate the value of the following expression: 123.45 + 678.9 − 45.67

Ques 2: Approximate the value of 15.7 × 6.9 ÷ 3.2

Ques 3: Approximate the value of the following expression: 245.5+39.88.4

Ques 4: Approximate the value of 33.6% of 198

Ques 5: Approximate the value of 1235

Ques 6: Approximate the value of 472.315.8​

Ques 7: Approximate the value of 39.7×4.2

Ques 8: Approximate the value of (225.4+174.9)÷9.8

Ques 9: Approximate the value of 68.9% of 505

Ques 10: Approximate the value of 87.5−29.6+43.7

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