Ti-68 Calculator
Named variables, and interactive formulas of up to 79 keystrokes, could be stored, subject to a total memory usage of 440 bytes. Some features included a simultaneous equations solver, a polynomial root finder, two-variable statistics, complex numbers, and a recall feature, which would display the last equation entered and its answer. It had several features useful to computer programmers, such as radix modes and conversions and bitset operators. It had an alphanumeric keyboard and display.
