Early adding machines
Both of these instruments were devised to add and subtract English money and so have wheels for farthings, pennies and shillings. Sir Samuel Morland's 17th-century example [1] has no mechanical connections between the sets of wheels: the user turns the wheels with a stylus and has to remember to carry tens manually. A century later Earl Stanhope invented a similar but more sophisticated device [2]. Neither were commercial successes.