DATAMATH  CALCULATOR  MUSEUM

# Pittsford, New York, September 17, 2009

Texas Instruments took in 1976 in conjunction with mathematics educators at two major universities an initiative to introduce a group of 6 calculators for educational use. Including the Little Professor, the limited function ABLE calculator, the colorful TI-1205 and TI-1255, the TI-30 and the sophisticated SR-51-II, these calculators helped students understand and use math concepts from kindergarten through college and career.

Till this day only the Sales Leaflet CB-272 distributed in 1976 through Texas Instruments’ Learning Center gave us the opportunity to picture these calculators side-by-side.

Exactly 10 years since the curator of the Datamath Calculator Museum signed membership at eBay (USA), the search for the last missing calculator found an end and the colorful TI-1205 arrived in the mail.

It took quite some patience, efforts, and last not but least some money, to acquire the three TI-1200 based calculators of the sextet. The whole story took off already in December 2001, when we revealed during our continuous research first pictures of the ABLE in the archives of the National Museum of American History. Pictures of the colorful TI-1205 and TI-1255 were known already from our fellow collectors Kirk B. Muri and Cleo McCall.

Despite the big efforts to hunt down rare calculators for the Datamath Calculator Museum took it till September 2007, before the first Texas Instruments ABLE was listed on eBay. It was no surprise that the auction price settled at a breathtaking \$211.50, understanding how rare the ABLE seemed then. Within barely one year, end of July 2008, Cleo McCall decided to sell parts of his impressive calculator collection and the Datamath Calculator Musuem was able to acquire his TI-1255 for a spectacular auction price of \$224.50. In September 2009 the rare TI-1205 appeared on ebay and here we are:

# How rare is this calculator?

This is probably the most put question to the Datamath Calculator Museum. The answer is not easy, but we have to factor in two figures:

 • How many calculators were manufactured and sold? • How many calculators survived?

The Texas Instruments Little Professor and TI-30 were manufactured in the millions and you find them still everyday on flew-markets, online auctions or as common trades between calculator collectors. The SR-51-II is slightly more difficult to find, it was neither very successful nor very reliable.

But the ABLE, TI-1205 and TI-1255 share a completely different story! In opposite to the very common TI-1200 and TI-1250 of the same era, were these three calculators sold only through a different sales channel to schools and other educational institutions in the United States and usually were scrapped after retirement. To make it worse from a collectors point of view - these calculators made use of two rechargeable NiCd batteries instead the common 9V battery. It was a matter of time and the AA-sized NiCd batteries started to leak and quite often destroyed the whole calculator. As a matter of fact survived only few of these calculators and (as of September 17, 2009) we know:

 Texas Instruments ABLE Serial Number Date Code Owner Remarks 10968 LTA 3776 Joao Oliveira 11051 LTA 3776 Robert Hartl 15324 LTA 3877 Kirk B. Muri 15339 LTA 4077 Joerg Woerner 15379 ? Ken Meine 15610 LTA 3877 Joerg Woerner 15619 LTA 4077 Joerg Woerner 29168 LTA 4077 Mark Bollman 29276 LTA 4077 Michel Zwawiak ? ? Smithsonian Institute 18579 MTA 2778 Trent Wray 19119 MTA 2178 Texas Instruments, Dallas

 Texas Instruments TI-1205 Serial Number Date Code Owner Remarks 13069 LTA 2776 Carl Benson 24835 LTA 4376 Lisa S. 1015016 LTA 1477 Godfrey P. Miles 1016099 LTA 1977 Joerg Woerner 1016188 LTA 1977 Kirk B. Muri 1026025 LTA 1278 Gilles Collas ? ? Smithsonian Institute

 Texas Instruments TI-1255 Serial Number Date Code Owner Remarks 1242627 LTA 1676 Joerg Woerner Prototype 12336 LTA 2776 Godfrey P. Miles Final Version 1003728 LTA 1777 Ken H. Meine Final Version ? ? Smithsonian Institute Final Version

Fellow collectors - if you own a Texas Instruments ABLE, TI-1205 or TI-1255 calculator,  please report us the serial number and date code from the back of the calculator for our Database.

If you have additions to the above article please email: joerg@datamath.org.

© Joerg Woerner, October 22, 2009. No reprints without written permission.