Texas Instruments TI-81 Handheld Electronic Calculator

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.

The back of the calculator has a compartment at the bottom that holds four AAA batteries as well as a small CR1616 or CR1620 battery. A mark scratched next to the battery compartment reads: R. The device has no serial number, but has a sticker at the top of the back that reads: Reconditioned. A sticker on the battery compartment cover reads: #30. Text on the back of the calculator indicates that the design was copyrighted in 1991. Text below this reads: MADE IN TAIWAN R.O.C.

According to the online Datamath Museum, the first examples of the TI-81 did not include the small battery.

This TI-81 was used in teaching mathematics at Amherst College in Amherst, Massachusetts. For software received as part of the same transaction, see 1999.3054.

References:

[Advertisement], Los Angeles Times, October 15, 1990, p. C16. New TI-81 calculator selling for $99.99. List price $129.95.

[Advertisement]. Washington Post, August 24, 1993, p. C10. TI-81 calculator, regularly $110.00, on sale for $69.99.

[Advertisement]. Washington Post, August 7, 1994, p. AE19. TI-81 calculator, list price of $115.00, on sale for $69.99.

[Advertisement]. Washington Post, September 4, 1994, p. F8. TI-81 calculator, regularly $115.00, on sale for $69.98.

Kidwell, P.A., A. Ackerberg-Hastings, and D. L. Roberts, Tools of American Mathematics Teaching, Baltimore: Johns Hopkins University Press, 2008, p. 309.

Online Datamath Museum, accessed June 12, 2015.

Texas Instruments, TI-81 Guidebook. A 1992 edition is online. Accessed June 12, 2015.

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