You can multiply and divide very large numbers, and even find square roots and cube roots without using a calculator!!!
You do not need to know your tables to use Napier's Bones.
They were popular around the world for hundreds of years.
Napier's Bones are the best known of the Maths Devices that John Napier Developed.
1 Have a look at the short introduction videos.
2 Print out some 'Bones' to build, or the simpler Napier's Bones Strips.
3 Try the examples, Don't worry you can always 'See Spike Do Them'.