The first mechanical calculator was invented in 1642 by the French mathematician Blaise Pascal. Interestingly, he didn't create it as a scientific experiment, but to help his father, a tax collector, with long and tedious calculations. Named the Pascaline, the machine could automatically perform addition and subtraction. About 30 years later, Gottfried Wilhelm Leibniz expanded on Pascal's idea by developing a calculator capable of multiplication and division. Today, the smartphones we carry in our pockets can perform billions of calculations every second, but the foundation of modern calculators was laid nearly 400 years ago with a simple goal: making everyday calculations easier.