Blaise Pascal was a mathematician most famous for creating the Pascaline, a type of early calculator. Sometimes referred to as the Arithmetic Machine, this simple calculator was only able to do addition, subtraction, multiplication and division.
Blaise Pascal was only 18 when he made his calculating machine. Originally created for Pascal's father in an effort to make his job as a tax calculator easier, the Pascaline was operated by turning a series of dials on the face of the machine. Pascal's design was so innovative that in 1649, Louis XIV of France granted him royal privilege. This decree gave Pascal exclusive rights to the production of calculators in France.
The Pascaline isn't the only scientific contribution Pascal is known for. He also did experiments with barometric pressure, studied the idea of perpetual motion and created the roulette machine. He was instrumental in the discovery of the mathematical theory of probability.