Page "Abacus" Paragraph 36

As a simple, cheap and reliable device, the Russian abacus was in use in all shops and markets throughout the former Soviet Union, and the usage of it was taught in most schools until the 1990s.

Even the 1874 invention of mechanical calculator, Odhner arithmometer, had not replaced them in Russia and likewise the mass production of Felix arithmometers since 1924 did not significantly reduce their use in the Soviet Union.

Russian abacus began to lose popularity only after the mass production of microcalculators had started in the Soviet Union in 1974.

Today it is regarded as an archaism and replaced by the handheld calculator.