How can you explain this? How do their orders differ?

Question

>>>"Aa"<"aa"
True
>>>"A"<"a"
True

Answer 1

This is because of their ASCII number, try to paste the following line in your console:

print( ord('A'), ord('a') )

You will see that the ASCII number of 'A' is lower than the ASCII number of 'a'.

This is why =====> 'A' < 'a' = true

Answer 2

Thanks!

Answer 3

I don't exactly understand that, I think that python only counts one character:

>>>"Aa"<"aa" # One character.
True
>>>"A"<"a" # One character.
True