It was advertised as offering logs, trig, and true scientific notation over a 200-
Unusually, it used reverse polish notation (RPN) ie. the operator was entered after the second number and so no equals key was needed.
For example to calculate 2 times 2, it is entered as:
+ (adds the 2 to zero)
Also, all numbers over 10 had to be entered as exponents, so 50 is entered as 5E1.
A big attraction was that it was so compact for the features it offered and easily carried around in the pocket.
The downside was that it was a bit flimsily constructed, especially the on / off key which was prone to wear and staying on permanently.
Sinclair Scientific and box.
Display was 5-
Released in 1974, the Scientific Programmable had a 24-
However, included with the calculator was a library of over 120 programs that performed common operations in mathematics, geometry, statistics, finance, physics, electronics, engineering, as well as fluid mechanics and materials science.
Green Vaccum Fluorescent display, showing program step number.