Judah Levin invented the calculating machine that used 10 keys to indicate numbers up to 9,999,999. It was designed to be a compact machine for addition and subtraction.
Yehuda Leib Levin was born on March 26, 1863. He was the son of Nachum Pinchas and was born in Traby, Vilna Province, Russian Empire (now a small town in Belarus).
Levin was an inventor by avocation and he secured three patents for the invention of his calculating machines (US706000 from 1902, US727392 from 1903, and US815542 from 1906).
Judah Levin’s adding machine had a steel frame, plastic and paper keys, and a leather and velvet suitcase. It’s overall measurements were 25 cm x 39.5 cm x 15.4 cm.