Napier's Local Arithmetic Board | STEM Montessori Math Learning Tool surgeon puzzle with its dimensions engraved into

with its dimensions engraved into the wood so the markings will not rub off with handling

Opthalmoscope

and it is the square

Mockingbird

No batteries

Napier's Local Arithmetic Board | STEM Montessori Math Learning Tool surgeon puzzle with its dimensions engraved intoJohn Napier was a brilliant Scottish mathematician who lived from 1550 to 1617. He developed a number of methods to simplify mathematic operations most notably logarithms but also some calculation tools like Napiers Bones and this Local Arithmetic Board. This board will allow the calculation of 2 numbers, though each number must be less than 512. It's an amazing thing to use this board and get a sense of the history as well as the mathematics behind