What is the Difference between combinations and permutations?

When we talk of permutations and combinations in everyday talk we often use the two terms interchangeably. In mathematics, however, the two each have very specific meanings, and this distinction often causes problems

In brief, the permutation of a number of objects is the number of different ways they can be ordered; i.e. which one is first, which one is second or third etc. For example, you see, if we have two digits 1 and 2, then 12 and 21 are different in meaning. So their order has its own importance in permutation.

On the other hand,  in combination, the order is not necessary. you can put any object at first place or second etc. For example, Suppose you have to put some pictures on the wall, and suppose you only have two pictures: A and B.

You could hang them

We could summarise permutations and combinations (very simplistically) as

Permutations - position important (although choice may also be important) Combinations - chosen important,
which may help you to remember