STEPPED RECKONER (Gottfried Leibniz) Stepped Reckoner â—¦The step reckoner (or stepped reckoner) was a digital mechanical calculator invented by the German mathematician Gottfried Wilhelm Leibniz around 1672 and completed in 1694. It was the first calculator that could perform all four arithmetic operations. The machine is about 67 cm (26 inches) long, made of polished brass and steel, mounted in an oak case. Stepped Reckoner was devised to perform addition, subtraction, multiplication, division and to find square root.
