This study occurred as part of a project entitled Collaboration for the Enhancement of Mathematics Instruction (CEMI). CEMI is a partnership involving middle and high school mathematics teachers, university mathematicians, university mathematics teacher educators, and pre-service secondary mathematics teachers. The purpose of the study is to examine how a multimedia case is perceived by four groups of people with diverse backgrounds and common interest in mathematics teaching and learning--pre-service secondary mathematics teachers, in-service secondary mathematics teachers, university mathematicians, and mathematics teacher educators. This research also considers the interactions of these groups as they meet both online and face-to-face to discuss the multimedia case. The multimedia case study "Making Weighty Decisions" was used to assist the four cultures in understanding each other's perspectives on mathematics teaching and learning prior to beginning collaborative lesson planning. (KHR)