MyMaths MyLife

Permutations and combinations is one of the important areas in many exams because of two reasons. The first is that solving questions in this area is a measure of students reasoning ability. Secondly, solving problems in areas like probability requires through knowledge of permutations and combinations.

If one operation can be performed in 'm' ways and, a second operation then can be performed in 'n' ways, the number of ways of performing the two operations will be m*n.

Permutations:
The different arrangements of a given number of things by taking some or all at a time,are called permutations.
eg:- All permutations( or arrangements)made with the letters
a,b,c by taking two at a time are (ab,ba,ac,ca,bc,cb).

ombinations:
Each of the group or selections which can be made by taking some or all of a number of items is called a combination.
eg:- All permutations( or arrangements)made with the letters
a,b,c by taking two at a time are (ab,bc,ca).