like terms

Like terms are terms that have the same variables. For example, 6n-2n. We could combine 100p and 3,000p because they have the same variables and like terms, they both have p. NO I can not combine p and p^2 because only one of the p are being square by it self and the other variable is just p. WE can not do 2d + 2f because it will just equal to 2d + 2f=2d + 2f it does no have like terms. Why not if you going to answer the question you have to put a equal sign so why not. Some question don't have a equal sign only equation have a equal sign. The perimeter is a measurement around a shape.