Approximation - Study Material

 Approximation

An approximation is an entity that is intentionally similar but not exactly equal to something else. The approach to solve approximation questions in various government exams like IBPS, SSC, Railways, PSUs etc. are similar to simplification. To solve approximation questions, we need to understand the foundation of simplification i.e. BODMAS.

B → Remove Brackets - in the order ( ) , { }, [ ]
O → Of
D → Division
M → Multiplication
A → Addition
S → Subtraction

Chronology of BODMAS Rule

Here are the steps to implement BODMAS rule in approximation questions:

Step 1: Identify & compute the brackets. Moreover, in solving brackets the order (), {} and [] should be followed..

Step 2: Compute Powers, roots.

Step 3: In the penultimate step, Perform division & multiplication (left to right as division & multiplication have same rank).

Step 4: Finally perform addition & Substraction (left to right as addition & substraction have same rank).

Q1: Solve 12 + 22 ÷ 11 × (18 ÷ 6)^2 - 10

Step1: 12 + 22 ÷ 11 × 3^2 - 10 (Compute Brackets first)

Step 2: 12 + 22 ÷ 11 × 6 - 10 (Deduce Exponents)
Step 3: 12 + 2 × 6 - 10 = 12 + 12 - 10 (Division and multiplication, left to right)
Step 4: 24 - 10 = 34 (Addition and Subtraction, left to right)

 

Q2: Solve 4433.888 - 2211.911 - 1133.546 + 3377.222

Tip: Solve this types of questions by approximating the value.

• 4433.764 = 4434
• 2211.993 = 2212
• 1133.667 = 1134
• 3377.442 = 3377
• 4434 - 2212 - 1134 + 3377 = 4466

Q3: Solve 38.73 x 15.11 - 27.88 × 10.23 = (20 + ?) × 4.89

Approximating value to the nearest integer,

39 x 15 – 28 x 10 = (20 + ?) x 5

585 – 280 = (20 + ?) x 5 (Multiplying LHS)

305 = (20 + ?) x 5 (Subtracting LHS)

305/5 = 20 + ?

61 = 20 + ?

? = 61 – 20

? = 41

Approximation: Frequently Asked Questions

Q1: What is Approximation?

Answer: Approximation is a process by which complex numerical expression are broken down into simpler form by performing various mathematical operations according to BODMAS rule.

Q2: In which exams questions related Approximation are asked?

Answer: Questions related to Approximation are asked in quantitative aptitude section of all competitive exams like IBPS, SSC, Railways etc.

Q3: How many questions are asked from Approximation?

Answer: On an average, 5-7 questions are asked from Approximation.

Q4: How can I solve Approximation questions?

Answer: Practice is the key. Improve your calculation speed & accuracy.