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)

Describes five computer-oriented activities suitable for middle grade students. Activities focus on use of spreadsheets to record nutrition data, programs that cause lights to twinkle on a Christmas tree and balloons to burst, an arithmetic problem, and a mathematics exercise using a spreadsheet. (JN)

Computer operations involving complex numbers, essential in such applications as Fourier transforms or image processing, are normally performed in a "divide-and-conquer" approach dealing separately with real and imaginary parts. A number of proposals have treated complex numbers as a single unit but all have foundered on the problem of the…