1976 -
Electronika B3-14M
The scale on the monitor: 1:1
Electronica B3-14M is the USSR’s simplest pocket calculator produced since 1975. This microcalculator is a modification of Electronica B3-14 manufactured in the same casing as B3-09M. The sale price was RUB 90 up to 1978 and RUB 55 later on.
The calculator uses the same K145 microcircuits as B3-09 and B3-14. The only difference with B3-14 is that B3-14M does not feature the percentage calculation function. Removal of selected functions was typical for many models of the Soviet microcalculators. In most cases, it all came down to calculators lacking the dedicated key, though technically they could still perform the missing function.
B3-14M-1

IMG_1517

IMG_1508

IMG_1512

B3-14M also had an eight-digit vacuum fluorescent display, just like B3-09M and B3-14.

For power supply the calculator can use both four AA batteries and a line adapter. Size — 158✕86✕36 mm. Total weight — 400 g.

Sources: http://www.enlight.ru/post/6067, http://statehistory.ru/1290/Pervye-sovetskie-mikrokalkulyatory/, http://www.leningrad.su/museum/show_calc.php?n=33.