Helpful Tip

Example:

How many possible arrangements can we have for the letters a, b, and c?

Solution:

The letters a, b, c can be arranged in these ways: abc, bac, cab, acb, bca, and cba

There are 3 positions available. There are 3 letters that can go into the first position. So we have:

3

AND

There are 2 possible letters that can now go into the second position. So to pick the second position we have:

2

AND

There is 1 letter that can now go into the third position. So to pick the third position we have:

1

So the number of arrangements for the 3 letters will be: 3 x 2 x 1 = 6
Put simply, it is 3! = 6

Now try these: