Learning mathematics with understanding is the vision of school mathematics recommended by the National Council of Teachers of School Mathematics (NCTM). In order to design and develop learning environments that promote understanding efficiently, teachers need to be aware of student difficulties in learning mathematics. Drawing from the research in mathematics education, this ERIC Digest focuses on student difficulties in learning written symbols, concepts, and procedures in elementary mathematics as well as the sources of these difficulties. Topics include difficulties in learning written symbols and difficulties in learning elementary mathematical concepts and procedures. (Author/MVL)