board pin

A pen is a writing instrument used to apply ink to a surface, usually paper, for writing or drawing. Historically, reed pens, quill pens, and dip pens were used, with a nib dipped in ink.

A calculator is a device that performs arithmetic operations on numbers. The simplest calculators can do only addition, subtraction, multiplication, and division. More sophisticated calculators can handle exponent ial operations, roots, logarithm s, trigonometric functions, and hyperbolic functions.