Greetings to everyone visiting from The Datamath 30th Anniversary Commemorative Edition!  Visitors: Click here to go to my main calculator page--and thanks for stopping by.

The Datamath or TI-2500 was released in 01972 and was Texas Instruments' first calculator.  It went through several modifications (this one isn't first-generation) before the Datamath II (TI-2500-II) followed a year later.

The Exactra name was used on several of the earliest Texas Instruments calculators.
1. Exactra 19.
2. Exactra 20.
3. Exactra 23.

Left to right, four variations on a theme:

1. Exactra-31: A desktop member of the Exactra line, brought out in the 01970's.
2. TI-3000: A slightly earlier version of the Exactra-31.
3. TI-3500: A contemporary of the TI-3000.
4. TI-4000

The TI-2550 line followed the Datamaths and Exactras.  These calculators introduced memory and some simple function keys.
1. TI-2550
2. TI-2550 II
3. TI-2500 III

1. Bowmar MX-55.
2. TI-5025: An early "pocket" printing calculator, this one is quite heavy and requires a large strong pocket.

My first calculator was a Novus Mathbox from 01977 like the one on the left here.  The decimal point on this model is fixed at 2 places, which enables the machine to get by with only 15 keys.  This calculator uses RPN logic.

For more from Novus/National Semiconductor, click here.

Not yet pictured:  Rockwell 8R and 20R.