Napier's Promptuary

Napier developed his Promptuary to solve a problem with his bones.

Using his bones to multiply your number by another number with more than one digit meant that you needed to write lines of part answers before adding to get your final answer.

Napier wanted his Promptuarys made to multiply numbers with up to 10 digits by numbers that also had up to 10 digit giving answers with up to 20 digits!

This needed number strips and covers with 60 accurate triangles on them. 100 cards and 100 covers are needed to allow every number to be used.

Have a look at the short introduction video.

Try a Promptuary example.

Try building a Promptuary. This needs to be done accurately.

Spikes version here is only 5 by 5 and only 25 cards and 25 covers, both half length. A great saving, but you can still multiply 10 by 10's with very little extra calculation.

Napier's Promptuary

Napier developed his Promptuary to solve a problem with his bones.

Have a look at the short introduction video.

Try a Promptuary example.

Try building a Promptuary. This needs to be done accurately.

Napier's Promptuary

Napier developed his Promptuary to solve a problem with his bones.

Have a look at the short introduction video.

Try a Promptuary example.

Try building a Promptuary. This needs to be done accurately.

Napier Maths