I teach 4 different math classes a day. It seems as though I am always reviewing key words that *usually* match with certain operations. While introducing variable expressions to my sixth graders, I had students make a 4 door foldable. On the front of each door they labeled Addition, Subtraction, Division and Multiplication. Students then brainstormed lists of words or phrases that correspond to each operation.
As a class, we listed words and the students recorded them in their math binders. We take it out when we word on problems and the students use it as a reference. I love the format of this foldable and have used it for other math and science topics.