The abacus is the first known calculating machine, made of beads and rods used for basic arithmetic. John Napier invented a calculating device using bone rods with printed numbers that could perform addition and subtraction. Blaise Pascal invented a calculating device using gears to represent digit positions. Later innovators like Gottfried Leibniz, Charles Babbage, and others continued developing calculating machines, leading to modern computers that now use integrated circuits, artificial intelligence and other advanced technologies.