Napier's Bones: Quickly Multiply, Wooden Style
9 Steps
I first encountered Napier's Bones back in Mrs. Hutnick's 4th grade EL math class. We had a 'build day' of sorts in which we made our own Napier's Bones, and at the time I thought they were really cool. Now, a bunch of years later, I still think they're really cool--they're very simple to make and to use, they are durable, and they can be personalized in any way you see fit.

My old pair is quite sloppy (though not bad for a 10-year-old, I'd say. Good job, former me), so I decided to make a new and improved set--documented here on Instructables.

Now for the important part: what Napier's Bones are. They are a multiplication tool/math toy that allows you to multiply 0-9 with large numbers extremely quickly with only slabs of wood. As long as you add small numbers and read correctly, you will get the correct solution every time.
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Step 1: How They Work

Watch the video below while relaxing to the smooth tunes in the background:

scrollsawcharlie says: May 16, 2010. 11:25 PM
I love this kind of stuff , Thank you, now am off to the shop to build my own
mashedpotato13 says: Mar 20, 2010. 8:02 PM
I actually made it into foam board.
E-R-IC says: Feb 12, 2009. 6:37 AM
can you multiply more digits?
joshf (author) says: Feb 12, 2009. 12:54 PM
if you make more bones, you can multiply more digits.
E-R-IC says: Feb 12, 2009. 1:09 PM
thanks for the fast answear
shamanwhitewolf says: Aug 10, 2008. 1:44 AM
This is great. I love playing with numbers (and I work with them a fair bit). This really wet my appetite, so I looked up some more info:
http://en.wikipedia.org/wiki/Napier%27s_bones

It adds to your explanation, and tells of more things we can do with it, making your Instrucatable even more valuable!
E-R-IC says: Feb 12, 2009. 6:44 AM
E-R-IC says: Feb 12, 2009. 6:34 AM
this pic might help:http://pages.cpsc.ucalgary.ca/~williams/History_web_site/Graphics/Napiers%20bones%20etc/napiers%20bones.gif
Cinders2001 says: Sep 7, 2008. 2:06 AM
Very well put together.....I just need to learn how to use them!! Probably easier than I thinkt....but i'm thick!! Thanks.
bkind2all says: Oct 23, 2008. 11:19 PM
as noted below, wikipedia explains.
bruno13069 says: Aug 9, 2008. 3:43 PM
Sometimes I'll draw a "Napier's grid" to do multiplication instead of trying to line-up all of the columns vertically. The first time I did this, I got weird looks from some friends, but I was doing (6 figure * 6 figure) multiplications faster than the rest of them.
frkohler says: Aug 8, 2008. 11:51 AM
Muito legal!!! Muito mais fácil de usar que o ábaco! Congratulações!
hammer9876 says: Aug 7, 2008. 3:39 PM
I love this! I'm thinking of building a couple of sets for my puzzle loving nephews. They should get a kick out of it. OK. It isn't a puzzle, I realize that, but because they like puzzles, we have the material because we keep making stuff for them. I am thinking though, that it would be great if the wood could be finished.
mattdonahoe says: Aug 7, 2008. 1:41 PM
Mrs. Hutnick? Nice. By the time they let me in her EL math class, it was the end of fifth grade and we were playing with platonic solids.
capricorn says: Aug 7, 2008. 2:48 AM
I love that :) Will do as soon i find the wood ;)
hornbadoing says: Aug 6, 2008. 2:30 PM
my new fevered Instructable
Doctor What says: Aug 5, 2008. 7:09 PM
I had to watch the video twice, but I get it. This is a really neat project!
Doctor What says: Aug 5, 2008. 7:11 PM
And I like your instructions. They are really thorough!
Tinker83 says: Aug 4, 2008. 11:46 PM
this is the method that was taught when my dad was in school. i don't recall him saying anything about using a tool like this, but the thought process was the same. it's disgusting how he can spout off a number before i can even get it written down.
Rob K says: Aug 4, 2008. 9:17 PM
Neat way to do math.
=SMART= says: Aug 4, 2008. 2:27 PM
I think i get it, ill have to make it and test it out :P Very nice way to work math out though : 5 *
jessyratfink says: Aug 4, 2008. 11:19 AM
I'm really happy you posted this. I now understand how to use them! I was at a bit of loss while you were working on them. :P