In how many ways 5 letters can be posted in 4 letter boxes ?

In how many ways 3 letters can be posted in 4 letter-boxes,if all the letters are not posted in the same letter-box

In how many ways can 5 letters be posted in 4 letter boxes?

In how many ways can 5 letters be posted in 4 letter boxes?

In how many ways 5 letters can be posted in 4 post boxes.

5 letters can be posted into 3 letter boxes in:

5 letters can be posted into 3 letter boxes in:

In how many ways can 7 letters be posted in 4 letter boxes?

In how many ways can 7 letters be posted in 4 letter boxes?

In how many ways can 4 letters be posted in 5 letter boxes?