calculating machine

A calculating machine is a machine designed to come up with calculations (i.e. computations); the most famous is probably the Victorian British scientist Charles Babbage's Difference Engine (No. 2), designed in the 1840s but never completed in the inventor's lifetime*.Calculating machines shouldn't be confused with adding machines, which are for solving sums.(* A working Difference Engine based on Babbage's original specifications, using only materials available during the mid-19th century, was built at the London Science Museum in the late 1990s.)
See more at Wikipedia.org...

Noun
1. a small machine that is used for mathematical calculations
(synonym) calculator
(hypernym) machine
(hyponym) abacus