Other Electronic Calculators
	Canon Pocketronic. Introduced in Japan in 1970 (!) and in the USA in 1971, this is the oldest electronic calculator in my collection As a matter of fact, this is the first handheld calculator that was mass-produced. It was based on the Texas Instruments Caltech project and used a thermal tape to print the results, as well as the numbers involved in a calculation. One other unique feature of the calculator is that is uses 6 AA and 7 2/3AA sized batteries, for a total of 13 rechargeable batteries. Original price:$395.00
	TI 2500 "Datamath". Introduced on September 21, 1972, this was Texas Instruments' first calculator. Compare this one to HP's first Calculator, the famous HP 35. This one is Version 3, introduced in August 1973. Original price: $120
	EC 312 - Astro. Manufactured by Radio Shack, this is a four basic function, as well as an astronomical calculator with a very unique design and fluorescent LEDs. It could provide biorhythms for any given birth date. It could also show compatibility between two persons base on their birthdays.
	CASIO micro-mini. Manufactured by CASIO, Japan, in the early '70s, this is one of the smallest calculators ever made. It had an unusual yellow LCD display. Its overall dimensions were: 1-½" x 2-¼" x 1/2". Original price: about $60
	Unisonic 21. This unusual calculator was manufactured in 1975 by Unisonic, a major pocket calculator manufacturer with, most likely, the most models than any other manufacturer of the times. It included a Blackjack game, endorsed by the famous casino player of the times, Jimmy the Greek. His signature can be seen across the top of the calculator.
	ICP 537. Manufactured in 1974 by International Consumer Products Ltd., a subsidiary of a US shopping center development company, who diversified in calculators for a short period. This was the first pocket calculator I purchased (well, my father did!).
	Sharp Elsi Mini EL810. Manufactured in
	Prinztronic Micro. Manufactured in
	Summit SE-88M. Manufactured in
	CalcuPen. Manufactured in
Other Mechanical Calculators
	Otis King Model "L". This is really a slide rule, rather than a calculator, but the design was so interesting, that we had to include it. It was made in England by Carbic Ltd., London, from 1921 until 1972 when electronic calculators made slide rules obsolete. It was 6" in length, but would extend to 10" for calculations.
	Halden's Calculex. A circular slide rule patented in England around 1910, although some versions may have been manufactured earlier, as the manufacturing company, J. Halden Co. Ltd. of Manchester, was established in 1877. Original price (in 1937): $9.15
	Fowler's Twelve-Ten. Manufactured by Fowler & Co in Manchester, U.K, around 1950, this circular slide rule had an unusual design: the scales would not rotate against each other. instead, the two hairlines were used to calculate the results. Several other models were produced with varying scales. The Twelve-Ten could calculate 10ths and 12ths of a number.
	VE-PO-AD. Introduced in the 1930s by the "Reliable Typewriter & Adding Machine Co.," Chicago, IL, it could only do addition and subtraction. Its name stands for "Vest Pocket Adding Machine."
	Baby Calculator. Mechanical calculator made in Chicago, IL capable of performing additions only.
	Swift Handy Calculator. Introduced around 1965. Used a stylus and could only do additions and subtractions by adding the 10's complement.
	Rolls Record 6.Manufactured some time in the 60's, also a mechanical calculator for additions only.
	Addometer. Also manufactured by Reliable Typewriter & Adding Machine Co. between 1900 and 1960. You could either add numbers by rotating the dials to the right, or subtract by rotating them to the left.
	Shop-n-add. Manufactured some time between 1920 and 1950, it was meant to be used during grocery shopping to add items purchased. Apparently, it was expected that a full shopping cart would not cost more than $9.99 during those times.
	Golden GEM. Manufactured originally in 1904 and on by the Automatic Adding Machine Co, New York, this Golden GEM 7-digit Adding Machine used chains to drive the numbers. On the face, it shows patents from 1904, 1906 and 1907.
	Burroughs Adding Machine (Class 3). Introduced in 1911 and was selling until 1927. Manufactured Burroughs Adding Machine Co, in Detroit, MI, it was a mechanical and printing calculator. These machines were extremely complex and have been known to incorporate anywhere from 3,000 to 5,000 moving parts in order to complete a calculation. Class 3 machines were called "visible models" because the operator could see the printing any time, something that Class 1 and 2 machines were criticized for. In later years, Burroughs merged with Sperry to form Unisys.