Mathematics curriculum documents highlight the need for students to be able to choose from a repertoire of computational tools and strategies, but little direction is given as to how children choose which form of computation to use in any given situation. In this article, the author reports on the classroom implications of research designed to determine the computation choices made by 10-12 year old students. He discusses which choices were made, why they were made and how successful students were in executing their choices. (Contains 2 tables.)