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. The name comes from the translation of the German term for its operating mechanism, Staffelwalze, meaning ' stepped drum '. It was the first calculator that could perform all four arithmetic operations.
who came up with the type of calculator known as 'the step reckoner'
German mathematician Gottfried Wilhelm Leibniz