Monday, February 27, 2012

Napier's Bones

Once students are comfortable with lattice multiplication, Napier's Bones is a great enrichment activity. Students order the bones as they would write the problem in the lattice. They are then able to read the answer without any writing. It's magic!

Download the Napier's Bones template that students may cut apart to create the bones. The file contains three different versions including blank bones that students fill in to create the bones, developing a richer understanding of the magic of the bones. Copy the handout on card stock and laminate before cutting to create more durable classroom sets.  Teachers may also elect to create a transparency of the bones and cut apart for use on the overhead.

Interactive Napier's Bones:
This site allows students to manipulate the Napier's Bones to multiply large numbers and check the accuracy of their answers.  Simply click on Get Multiplication to start, then click the appropriate bones to add them to the problem on the left.  Students then read the correct answer, post it in the answer box and click Check answer.

Note that the site may also be used to do any problem.  Simply click Reset, then click on the bones needed, and read the answer.  This would be a powerful introduction to Napier's Bones using a whiteboard or projector. 


  1. We love Napier's Bones. We made some on tongue depressors!

    1. I've also done this with students and they're quite durable. No matter how they're made, students just love them!!!