Question

A keycode must contain 2 letters and 3 numbers. The letters may be any letter of the alphabet. The numbers should be any number from 0 to 9. How many different keycode combinations are there?

Answer 1

Hi! So what you need to know about combinations is that you can multiply possible events to get the combinations of all events. For example, if the combination was just two numbers 1-9, we know that each "slot" of the combination has 9 possibilities, so we can do 9*9, for  a total of 81 possible combinations. Does that help? If not I can explain further. 

Answer 2

If its including the number 0

Then there is 676,000 combinations

Explanation:

26*26*10*10*10=676,000 combos