How many different 4 letter license plates can be made using only letters m a t and h all four letters must be used on each plate?

To create a 4-letter license plate using the letters m, a, t, and h, with all letters used, we need to calculate the number of permutations of these 4 distinct letters. The number of permutations of 4 distinct letters is given by 4! (4 factorial), which equals 24. Therefore, there are 24 different 4-letter license plates that can be made using the letters m, a, t, and h.