Well, first consider how many digits there are. You have 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0, depending on how you use it, that are all digits. If you count 0 as a digit other than a place holder (0000, 0001, etc.), you would end up with ten thousand (10,000) numbers with four digits, starting with 0000, and ending with 9999. If you count 0 as nothing other than a place holder (1000, 1001, etc.), you would have nine thousand (9,000) numbers with four digits, starting with 1000. So, depending on how you view 0, you can make up to 10,000 different numbers that contain four digits.
Well if you are talking to me about the following graphic <span>http://contentlaunch.ple.platoweb.com/testimagedb/53/5377183edb46ae5c5177efb0f9dfbbd1 then we have to say that it would be 4,1. Right there you can find A. Hope this has helped you</span>