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 Problems on Numbers section you need to update more questions to perform well in front of job recruiters and companies. Problems on Numbers Interview questions are most important to score in interview, Update all questions to score well in all rounds in job interview.

# Problems on Numbers Formula

**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