Question 548883
Since ORDER MATTERS, we are dealing with a permutation 

for the first letter we have 26 choices. 
For the second letter we have 26 choices( since we can repeat letters)
For the first number, we have 10 choices.
For the second number we have 10 choices. 
For the third number, we have 10 choices. 
and for the fourth number we have 10 choices. 

Using the product rule, there are 
{{{26*26*10*10*10*10=26^2*10^4=6760000}}} different license plates.