How does napier bones work?

Napier's bones is a manual calculation tool that uses a set of rods, each marked with digits, to perform multiplication and division. Each rod represents a digit from 0 to 9, and the multiplication of a number can be visualized by aligning the rods corresponding to the digits of the multiplier and reading off the results. By shifting and adding the values from the various rods, users can efficiently carry out arithmetic operations without the need for a calculator. This method was invented by John Napier in the early 17th century to simplify complex calculations.