The TI-81 first graphing calculator sold by Texas Instruments,

Description: This is an example of the first graphing calculator sold by Texas Instruments. The TI-81 was introduced in 1990. The handheld electronic calculator has a blue plastic case with a sliding cover that can also serve as a stand. It has an array of forty-one rectangular plastic keys, many of which can take on three meanings. These include a wide number of arithmetic, trigonometric, statistical, and algebraic functions. Letters of the alphabet also can be represented. The calculator also has four arrow keys, plus a row of five keys immediately under the display that relate to graphing. In addition to performing a wide range of calculations, the calculator could display eight lines of text sixteen characters long or graph up to four functions simultaneously. A mark above the display reads: TEXAS INSTRUMENTS TI-81. This TI-81 was used in teaching mathematics at Amherst College in Amherst, Massachusetts. For software received as part of the same transaction, see 1(contact info removed)