The four-function calculator is widely used by students and teachers in elementary schools. Although other types of calculators are available, the number of choices has been limited up to now. Recently, however, calculator manufacturers, including Casio (fx-991Wplus, fx-115Wplus, and fx-300Wplus), Sharp (EL-520RB and EL-506RB), and Texas Instruments (TI-30X IIS, TI-34 IIX, and TI-15), have introduced two-line calculators, and more are being developed. These calculators can display an expression on one line and the computed result on the second line. These calculators offer a variety of features in addition to the two-line display, but this article focuses on the development of numbers and operations using the TI-15, which is specifically designed for use in elementary school and middle school classrooms.
St. John is interested in the impact of technology on the mathematics curriculum, and Lapp is interested in using multiple representations with technology for teaching mathematics. Readers are encouraged to send manuscripts appropriate for this department to “Tech Time,” NCTM, 1906 Association Drive, Reston, VA 20191–9988.