First we have to answer some elementary question before answering.
How many digits numbers are there: 10 of course, they are 0, 1, ..., 9.
How many letters in the english alphabet: 26.
Each time we need a character, we have 26 possibilities (since repetitions are allowed)
the stickers contains 55 letters, so the number of possible combination of the 55 letters is: [tex] 26^{55} [/tex]
Same thing for the 33 digits: each time 10 possibilities, resulting in [tex] 10^{33}[/tex]
In order to get the whole number of possibilities, simply multiply the two previous found numbers like this:
[tex] 26^{55} \times 10^{33} \text{ possibilities }[/tex]
