Before Applying job posting in any websites or recruiting agencies or sending resumes to job recruiters or any other employment website you need to improve your skills on general knowledge, Aptitude, Puzzles, logical reasoning, general english, database, programming as per your job profile. Job recruiters or mostly preferring job candidates who are having more stuff in those categories mentioned above. So improving more skills on your job profile always boost up your career and your performance. Even hiring companies and job recruiters who are looking for many job posting websites actually they are looking and filtering on these activities. In these Numbers section you need to update more questions to perform well in front of job recruiters and companies. Numbers Interview questions are most important to score in interview, Update all questions to score well in all rounds in job interview.

# Numbers Formula

**Types Of Numbers**

**Natural Numbers**

Counting numbers are called natural numbers (1,2,3,4,5,6,...)**Whole Numbers**

All counting numbers and 0 form the set of whole numbers.

Every natural number is a whole number and 0 is a whole number which is not a natural number.**Integers**

All counting numbers, Zero and negatives of counting numbers form the set of integers.**Even Numbers**

A counting number divisible by 2 is called Even Number.**Odd Numbers**

A counting number not divisible by 2 is called Odd Number.**Prime Numbers**

A counting number is called a prime number if it has exactly two factors, namely itself and 1.**Composite Numbers**

The natural numbers which are not prime are called composite Numbers.

**Basic Formulae**

- (a + b)(a - b) = (a2 - b2)
- (a + b)2 = (a2 + b2 + 2ab)
- (a - b)2 = (a2 + b2 - 2ab)
- (a + b + c)2 = a2 + b2 + c2 + 2(ab + bc + ca)
- (a3 + b3) = (a + b)(a2 - ab + b2)
- (a3 - b3) = (a - b)(a2 + ab + b2)
- (a3 + b3 + c3 - 3abc) = (a + b + c)(a2 + b2 + c2 - ab - bc - ac)
- ( 1 + 2 + 3 + .....+ n) = n (n + 1 ) / 2
- (1² + 2² + 3² + ..... + n²) = n ( n + 1 ) (2n + 1) / 6
- (1³ + 2³ + 3³ + ..... + n³) = n² (n + 1)² / 4