Sumlock Anita Electronics Ltd. started making Rockwell calculators
after they were bought by Rockwell International in 1973.
The 10R is the least sophisticated of the Rockwell calculators made at the
Portsmouth factory. The image on the right (click to enlarge) is of a contemporary advertising
poster showing a range of the rockwells, from the 10R (left most in group) to the 61R,
the main image being of a 20R
This particular 10R calculator has an I.C. date stamp of 7514 (week 14, 1975).
It is smaller than the others, with only four rows
of keys, and no dedicated equals key---the plus key doubles up for this
function. So adding two and three becomes 2 += 3 +=. This is effectively
using the natural chaining that exists in the calculators, where the
equals key is in fact redundant. Not mentioned in the manual, but if one
wishes to continue a calculation after the += has been pressed, then by
pressing 0 before the desired function will allow further processing. So,
for example, if after the sequence 2 += 3 +=, one wishes to multiply
the result (which is 5) by 6, then press 0 x 6 +=, to give 30.
Try it out on the above image---it works!
There is no Rockwell manual for the 10R, but a manual for the
Sears 801.58190, which is the identical calculator save for its
casing, can be found on the
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Last updated 27th May 2006.
© 2004-2005 Simon Southwell. All rights reserved.