First Handheld Scientific Calculator

HP-35 CalculatorJanuary 4, 1972

Hewlett-Packard introduces the first handheld scientific calculator, the HP-35. The precision of the calculator was greater than most mainframe computers of its time. For such a technological achievement, the name of the calculator is simply derived from the fact that it has 35 buttons. I wonder if they had to use the calculator to figure that out.