What is the difference between permutation and combination /how should we identify them?
Permutation Suppose we want to find the number of ways to arrange the three letters in the word CAT in different two-letter groups where CA is different from AC and there are no repeated letters. Because order matters, we’re finding the number of permutations of size 2 that can be taken from a set of size 3. This is often written 3_P_2. We can list them as: CA CT AC AT TC TA Combination When we want to find the number of combinations of size 2 without repeated letters that can be made from the three letters in the word CAT, order doesn’t matter; AT is the same as TA.
