Texas Instruments TI-81

The TI-81 is the first graphing calculator made by Texas Instruments. It was designed in 1990 for use in algebra and precalculus courses. Since its original release, it has been superseded several times by newer calculators - the TI-82, the TI-83, the TI-83 Plus, TI-83 Plus Silver Edition, the TI-84 Plus, the TI-84 Plus Silver Edition, and most recently the TI-Nspire and TI-Nspire CAS; most of these share the original feature set and 96×64-pixel display that began with this calculator.