Answer: To calculate math equations
One look at this strange machine could leave you feeling overwhelmed and confused. However, the numbers probably gave some of you a clue as to what this machine was used for back in the day. This large machine is an early version of a calculator! The dials and levers were used to calculate equations quickly. This particular model was called the Marchant XLA calculator, and it was produced in the late 1910s. Not everyone had one of these in their homes. It was mostly used by large companies and offices.
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