Molly and Arthur are taking their daughter Ginny on a roller coaster ride. For safety, they need to find their total weight before getting into the same car. Molly’s weight is MMM kilograms, Arthur’s weight is AAA kilograms, and Ginny’s weight is GGG kilograms. The expression (M+A)+G(M+A)+Gleft parenthesis, M, plus, A, right parenthesis, plus, G describes their total weight. We can also use the expression A+(G+M)A+(G+M)A, plus, left parenthesis, G, plus, M, right parenthesis to represent the same quantity.