Prices dropped as new features were added and sales doubled each year. By 1976, a four-function calculator cost only a few dollars. In 1972, 5 million calculators were sold in the US and within ...

He then went into the arithmometer, which is arguably the first commercially successful mechanical calculator with four functions. That was around 1821 or so. But [Dan] mentions it used a Leibniz ...

Desmos offers a variety of math tools online. Many are calculators, including “a four-function, scientific, and graphing ...