IBPS Quantitative Aptitude Online Course Chapter 1

This is first chapter of IBPS Quantitative Aptitude online course. I will write series of chapters to cover all topics of Quantitative Aptitude. The chapter details with basics of Number System, Basic equation operations and Algebra formulae.

Most exams have two to three questions from this section. Also this section is very easy. You will have to be good into calculation.You should solve the problems faster. There are some basic rules which you should be aware of to solve problems faster than others.I have listed basic concepts and short cuts which you must remember.

Even Number

Number divisible by 2 is even number like 4,6,8

Odd Number

Number not divisible by 2 is odd number like 13,15,99

Prime Number

Number divisible by 1 and itself is prime number like 13,19,17

How to find if a large number is prime?

For now try to understand the concept we will see in example how to use them,

    • Find square root of the number
    • Make list of all prime number less than the square root of the number
    • If the number if not divisible by all prime numbers less than square root of number then the number is prime.

Division Rules

In exams there is one question in which you will have to find whether a number is divisible by another number. Below table helps you with that kind of question. You should remember these basic rules to know the answer looking at options itself.

      • A number is divisible by 2 if it ends in zero or in a digit which is a multiple of 2 i.e. 2,4, 6, 8.
      • A number is divisible by 3, if the sum of the digits is divisible by 3.
      • A number is divisible by 4 if the number formed by the last two digits is divisible by 4.
      • A number is divisible by 5 if it ends in zero or 5
      • A number is divisible by 6 if it divisible by 2 as well as by 3.
      • A number is divisible by 8 if the number formed by the last three digits is divisible by 8.
      • A number is divisible by 9 if the sum of its digit is divisible by 9
      • A number is divisible by 10 if it ends in zero.
      • A number is divisible by 11 if the difference between the sums of the digits in the even and odd places is zero or a multiple of 11.

BODMAS Rules

BODMAS rule defines the order in which expression should be performed. It is important to keep this rule in mind while solving arithmetic expressions. Every exam have questions related to BODMAS rules.

  • B – Bracket
  • O – Of
  • D – Division
  • M – Multiplication
  • A – Addition
  • S – Subtraction

Brackets should be evaluated in order () , {} , []

If there is a bar present in expression then that should be evaluated first.

Algebra Formulas for faster calculation

You can use these formulas to Multiplication and division problems in exams faster. We will see in solved question segment how to use formulas to solve complex multiplication and division problems. Exams will have questions which ask you to multiple or divide two big numbers. These formulas will help you calculate the results faster.

algebra-formulas-one

algebra-formulas-two

Algebra formula for powers

You can use these Algebra formula for questions having power of numbers.These exams have power of a but the formulas are true if you replace a by any number. So in exam problems if you have numbers then you can use below formulas to simplify them.

algebra-formula-three

Algebra formula for roots

You can use these Algebra formula for questions having root of numbers

algebra-formula-four

Important Formulas

Formulae 1

When two numbers divided by third number leave the same remainder then difference of the two numbers is also divisible by the third number. This can be used in solving problems which says if two numbers are divided by third numbers leaving same remainder find the divisor or remainder.

For example if the two numbers are A and B and third number is C then A -B is also divisible by C.

Formulae 2

(a + b) * (a+ b) – (a -b) * (a -b) = 4*a*b

where a and b can be any number. You can use this equation to solve problems where sum and difference of numbers are given and you have to find the numbers or similar combinations..

Formulae 3

Square of a number will have 0,1,4,5,6 or 9 as the last digit. Second last digit will always have be even number except if the last digit is 6. If the last digit is 5 then second last digit will always be 5.

Formulae 4

Square of a number can be written in form of 3n or 3n+1 or 4n or 4n+1 where n is any number. For example 49 can be written as 3*16+1 or 4*12+1.

Please proceed to Chapter two for formulas and tips and tricks for other sections of the exams.

Click here to read Chapter two