When i add or subtract polynomials, the degree adding together too? ex: 5x^3-2x^2+7x^2, the degree staying 3 or 2? or we add them?

When I add or subtract polynomials, the degree adding together too?
 Ex: 5X^3-2X^2+7X^2, the degree staying 3 or 2? Or we add them?  

5X^3-2X^2+7X^2
5 x ^3 + 5 x^2

Adding polynomials: simply add the like terms together. Like terms are terms with the same variables and exponents.

Subtracting polynomials: reverse the sign of each term (in other words turn "+" into "-", and "-" into "+"), then proceed to addition.

Do not add the exponents.