Next time you calculate a tip, thank Blaise Pascal, namesake of a fundamental law of pressure and inventor of one of the first digital calculators (a replica of which is pictured above). He was born #OTD in 1623. . . . . . . . #math #science #calculator #calculate #tip #money #addition #subtraction #inventor #history #howthingswork #numbers #add #subtract #sciencehistory #invent #discover