In some cases,the small number string is greater than big number string.

such as '2' is greater than '1000';

but '1' isn't greater than '1000';

and '2' isn't greater than '300'

I know that I am trying to comparing string,not a real number type,and it should be compare as lexical comparition.

I wanna ask what's the calculation principle of when these tow number string are comparing.