I need help with this difficult word problem

Question

Before the 1976, California license-plate numbers consisted of three numbers (for example, EGT 893). In the summer of 1976, however, the state ran out of numbers of this type and started issuing seven-digit plates (such as GIR 788 1). How many possible license plate numbers can be made from 3 letters followed by 4 numerical digits? (Base your answer on 26 letters in the alphabet and 10 numerical digits.)  

Answer 1

There may be 3 letters (A-Z) with 4 numbers (0-9), so

     26*26*26*10*10*10*10  = 175760000  possibilities

Answer 2

Since repetition is allowed and order does make a difference, the number of plates is:

 

26 · 26 · 26 · 10 · 10 · 10 · 10 = 4569760000