A pair of abacuses is used to illustrate addition, subtraction (by adding complements), multiplication, and division, with simplified examples given to illustrate the various features of each operation. Also indicates how this information can help students understand computer operations. (JN)

Presents background information and the listing for a LOGO computer program which investigates an ancient mathematical riddle (related to the square root of seventeen). The simulation, written for Apple II microcomputers, can be easily adapted to other microcomputers. (JN)