Napier's Bones: Quickly Multiply, Wooden Style

Step 3 Cut the Wood

Before you cut the wood, you want to decide how many pieces you want in your set. A set of two bones would be the minimum: you would be able to multiply some two digit numbers. I chose to make a set of four free bones, which covers every two digit number*, most three digit numbers, and about half of the possible combinations that entail four digit numbers. Also consider the size of your set: too many bones will no longer make your set portable and easy to use.

*NOTE: This numbering system does not include 1s and 0s in them--this is because 1s and 0s are not very interesting mathematically here, or not interesting enough to warrant more bones, in my opinion. If you want to include these numbers, you'll have to renumber some bones or make more.

For a set of four free free bones, you need to cut:
Five 9" pieces of your 1"x1" or 3/4" x 3/4" pole of wood
One 3.5" piece of the pole of wood

You need one more than the number of free bones because one bone needs to be fixed. The other piece is the base, so the length is dependent on how many bones you will make. (More bones, longer piece.)

I used a chop saw and a ruler to make the cuts, then sanded down anything not smooth.

You also need to cut the hardboard: measure out a size that is the width of one large piece and the length of the small piece added together, and then cut. I used the circular saw again, flipping it to cut the whole thing.