David Skinner in The New Atlantis:
One has to think of such prosaic activities as paying the mortgage and grocery shopping to be reminded of the quiet and non-revelatory quality of rudimentary arithmetic. Which is not to put such labor down. Adding the price of milk and eggs in one’s head is also brain work, and we should never forget the central place of mere calculation in the development of more sophisticated areas of human knowledge.
Long before the dawn of calculators and inexpensive desktop computers, the grinding work of large problems had to be broken up into discrete, simple parts and done by hand. Where scads of numbers needed computing—for astronomical purposes at the Royal Observatory in Greenwich, England, or to establish the metric system at the Bureau du Cadastre in Paris—such work was accomplished factory-style. In his book When Computers Were Human, a history of the pre-machine era in computing, David Alan Grier quotes Charles Dickens’s Hard Times to capture the atmosphere of such workplaces: “a stern room with a deadly statistical clock in it, which measured every second with a beat like a rap upon a coffin-lid.” The most famous modern example of such work is probably Los Alamos, where scientists’ wives were recruited in the early stages to compute long math problems for the Manhattan Project.