26 * 25 * 10  __  __  __  __  __

Now the numbers... no restrictions yet.
 

Suppose the first number is a 6:

26 * 25  6  __  __  __  __  __
Now, this guy can't be a 6...
9 possibilities


26 * 25 * 10 * 9  __  __  __  __
 

Suppose these are the first two numbers:

26 * 25  6  4  __  __  __  __
This guy can't be a 4...  But, it CAN be a 6
9 possibilities again!
 

26 * 25 * 10 * 9 * 9  __  __  __
 

Can you figure out the rest?

26 * 25 * 10 * 9 * 9  __  __  __  =  _______

 


TRY IT:

How many CA license plates are there if no two adjacent numbers or letters can be the same?