Like Terms

My definition of like terms is that like terms are terms with the same variable and exponent.
100p and 3000p are like terms.I can combine them because they have the same variable and exponent. p and p2 are not like terms they have the same variable but not the same exponent,
therefore you cannot combine them. We cannot combine 2d and 2f because they do not have the same variable or exponent. An expression cannot have an equal sign because you cannot combine unlike terms. You can only simplify an expression. Unless all of the terms are alike. A perimeter
is the distance around an object.