Terminated: unknown
From its manual:
Your Rockwell 61 R uses one of the most sophisticated electronic devices on the market: a single microelectronic silicon chip. This device is no bigger than a fleck of confetti, yet it is programmed to provide the capabilities for solving many types of complex problems. Rockwell International has had more experience with these remark- able devices than anyone else in the industry.
It has with trigonometric functions, logarithms,
and memory (including M+x2) and angle conversion.
As a scientific calculator its usefulness is limited by its inability to work
with exponential numbers.
Your Rockwell 61 R uses one of the most sophisticated electronic devices on the market: a single microelectronic silicon chip. This device is no bigger than a fleck of confetti, yet it is programmed to provide the capabilities for solving many types of complex problems. Rockwell International has had more experience with these remark- able devices than anyone else in the industry.
Errors are indicated by a big green dot at the left of the display. Above that dot there is an indicator for negavive values.
The four basic functions are automatically repeated when pressing the = key.
The xy function only accepts non-negative values of x.
It does not have a key or function for squaring numbers, but the × = key sequence works for that and the xy can be used.
There is a hint at the back with an example on how to calculate 5×5×5: press 5 × × =. The last operation and operand are reused when pressing =.
Another example: to calculate 15÷5 press 1 5 ÷ 3 =.
Now, to divide any other number by 3 also simply type that number followed by pressing = again.
One thing though, the placement of some of its keys, especially the = key, is awkward.
The CF function can be used to undo accidentally having pressed the F modifier key.
The DR function, which stands for Data Recovery, activated by pressing F twice, undoes the last number typed. If one wants to continue entering numbers use CF first to undo the F modifier now active.
It has a built-in battery pack, which has been removed from this specimen. It still runs perfectly on a 4.5 V power adapter.
Take a look at this calculator’s more powerful sibling, the Rockwell 63R. There is also a Russian copy of this calculator with exactly the same key layout and key shape, the ELEKTRONIKA MK 18M.
There is an article about this calculator on the Smithsonian website here (link validated 2026-01-29).