Simplifications are very important in Bank Exams. In Quantitative Aptitude /Numerical Ability section, about 40 - 50% of questions in clerical exam and about 20 - 25% of questions in Probationary Officers exam will be of simplifications.
All simplification questions are to be solved based on BODMAS rule only.
B - Bracket
O - Of
D - Division
M - Multiplication
A - Addition
S - Subtraction
When there are more brackets in the given expression, simplification should be started from inner most bracket to the outer most bracket.
Some Important Identities
* (a + b)2 = a2 + b2 + 2ab
* (a - b)2 = a2 + b2 - 2ab
* (a + b) (a - b) = a2 - b2
* (a + b)3 = a3 + b3 + 3a2 b + 3ab2
* (a - b)3 = a3 - b3 - 3a2 b + 3ab2
* a3 + b3 = (a + b) (a2 − ab + b2)
* a3 - b3 = (a - b) (a2 + ab + b2)
* (a + b + c)2 = a2 + b2 + c2 + 2ab + 2bc + 2ac
* a3 + b3 + c3 - 3abc = (a + b + c) (a2 + b2 + c2 - ab - bc - ac)
Laws of Indices
Squares and Cubes of numbers are very useful in simplification questions. Following table gives squares and cubes of 25 numbers