If a car tag starts with two letters followed by four numbers how many different combinations are there?

easy 26*26*10*10*10*10= 6,760,000 different combinations

Assuming that all ten digits are allowed, and all twenty six letters are allowed, the possible combinations are:

26 * 26 * 10 * 10 * 10 * 10 = 6,760,000

Since you didn't mention which language are the letters, i'll give you an answer in case you asked on the Hebrew alphabet ;-) It's 22*27*10*10*10*10=5,940,000

1: Assuming all 26 letters of the English alphabet are allowed, including I and O; that comes to 26 x 26 = 576 letter combinations.
2: but assuming no leading zeros are allowed (I've never seen them on car plates) and neither is the number zero, then the 4-digit numbers allowed are 1000 thru 9999, ie 9000 different number cpmbinations'
Thus the total numer of combinations comes to 576 x 9000, or 5,184,000.

Leading zeroes are allowed on UK trade plates, e.g. 047 FY. I'm pretty sure I've seen them on the new format Spanish plates. Satguru will know....

I'm not even sure this question will remain -- So, for the time being...let's pretend zero is a real number and base our combinations on that.

When setting this basic 'counting techniques' question in a Maths class to illustrate the Multiplication Principle, it is often followed by provisos,such as:
*What if the first digit cannot be zero?
*What if we don't use I and 1 because they look the same?
*What if we don't use O and 0 because they look the same?
*What if the two letters have to be different from each other?
*What if the digits are not allowed to repeat?
etc. (I had never thought of adding other alphabets! Even more interesting.)

http://www.usyd.edu.au/stuserv/documents/maths_learning_centre/countingtechniques.pdf