Define, simplify, add, and subtract polynomials. Identify the degrees of a polynomial. Determine if a polynomial is a monomial, a binomial, or a trinomial. Then look at simplifying a polynomial by combining the coefficient values of like terms. This resource contains clear steps leading up to and including how to add and subtract polynomials. Note: Be careful with subtracting polynomials because the signs of the terms inside the parenthesis will change.