A California license plate starts with a digit other than 0 followed by three capital letters followed by three digits (0 through 9). How many different California license plates are possible?

I will use a slot set up, and fill it in with the info given:

__ __ __ __ __ __ __

the first number can't be zero, this means there are 9 options for the first letter

for the 3 letters, there are 26 options for each letter

the last three numbers include 0, this means there are 10 options for each number

__ __ __ __ __ __ __

9 26 26 26 10 10 10

to account for all the options, the options for each slot should be multiplied

9 x 26 x 26 x 26 x 10 x 10 x 10 = 158,184,000 different licence plates possible