I developed this work for Micah who at the time, 1) started everyday with the bead stairs because she thinks it looks like a rainbow, and 2) needed particular attention to her fine motor skills so she can write soon.
You will need the Montessori numerical beads. If you don't have these, a quick trip to an arts and crafts or jewelry store should get you the beads and copper wires you need to make your own (this should be fun)! Here are the colors: 1-red, 2-green, 3-pink, 4-yellow, 5-light blue, 6-purple, 7-white, 8-brown, 9-dark blue.
You also need clay in those colors, which are easy to find in toy stores (or if you are feeling do-it-all-yourself, you always can). I found the perfect container for my clay, a 9-compartment drawer in the DIY Store.
I took a shot at a little woodwork / "carpentry" and made a 4x4-inch wooden tablet on which I drilled grooves that were just the size of the beads. I like this because it makes the work more Montessori, but you can always improvise and simply build on a felt cloth or a masonite board instead.
Make sure to emphasize the dominant hand's pincher grip (thumb, pointer, and middle finger). This develops fine motor skills and is an indirect preparation for writing.
This is a popular albeit long work. Just be patient with those bits of clay that can stubbornly stick on soles and socks; you can ask the children to work on a newsprint and sweep after.