The sign greater than "$>$" represents the quantity of one number more than another number. However the same sign is used to know the direction of a number on the numberline ( with respect to an another given number ). So $5 > -5$ holds true.
However, in reality there is no difference in the quantity of two numbers. They are just on opposite side of origin. Isn't it an ambiguous trend to calculate in math ? Is there any other way to represent the same thing that makes sense?