To add polynomials of any size, just group like terms and then combine them together. To see it done step-by-step, watch this tutorial!
Combining like terms together is a key part of simplifying mathematical expressions, so check out this tutorial to see how you can easily pick out like terms from an expression
Subtracting polynomials? No problem! Just distribute the negative sign to the second polynomial and then combine like terms. Watch this tutorial to see how it's done!