What happens when you divide by zero on a mechanical 1950s calculator? In the 1950s, mechanical calculators didn’t have the safety checks of modern machines. So when someone tried to divide a number by zero, the calculator didn’t display an error. Instead, it would enter into a chaotic loop, spinning its gears uncontrollably. This endless motion happened because the machine was trying to calculate something undefined, and it simply didn’t know when to stop.