Terminated: 1976
It is a big and heavy 8 digit calculator with a LED display, memory and percentages.
It runs either on four non-rechargeable AA batteries, or on three rechargeable NiCad batteries, leaving one slot empty. If using a power adapter, there are two versions, see illustration.
Use the "F 2 3" slider to switch between floating point, or rounded currency modes with a mantissa of two or three decimals.
A non-zero value in memory is indicated by lighting up the top left and top segments of the leftmost digit. The effect of this is that a small "c" is visible top-left when there is a non zero value in memory and a negative number is displayed.
Funny enough, erros are indicated by lighting up the bottom left and bottom segments. So when a "E" is displayed, the calculator has an error condition with a negative number displayed and a non-zero value in memory. :-)
The last operation is repeated when the "="-key is pressed.
There is a page on this model on the site of The National Museum of American History, see it here (link validated 2024-07-16).