Base ten ziggurat

While I’m not as crazy about base ten blocks as I am about fraction tiles, they’re a great tool for de-mystifying ones and tens and hundreds.  And if you play your blocks right, you can also use them for illustrating tenths, hundredths, and thousandths (the flat that looks like a hundred gets used as a one, kind of like a dollar made up of a hundred pennies, the rods become tenths, and the small cubes become hundredths).  You can also get little sliver blocks to use as thousandths. You’ll just want to be careful not to switch over too quickly and cause confusion.

Plus, you can build things like ziggurats with them, like the family who sent me this photo did:

It might be tempting to get frustrated if after purchasing a set of such blocks they seem to be used primarily as building materials.  But just having the blocks around can plant seeds of conceptual understanding. (The very seeds which were never planted for so many of us, such that our math knowledge was confined to what we could remember of facts and procedures.) It’s hard not to handle them without getting the hang of the whole tens business.

*If you decide you could use some of these in your family, here is a bit of information about different varieties of blocks.  

The ones shown above are non-interlocking, so each block is discrete but you can stack them so they precisely show the relationships between the cubes, rods, and flats.

I prefer those to the interlocking kind, which are helpful because you can turn ten cubes into a rod, but are not as precise in their spatial relationships to each other (because they have knobs that allow for the interlocking, so the space taken up by ten cubes is more than a whole rod, by the size of the knob on the last cube in a given row).  

You can also get a set that’s magnetic.  The thing about the magnetic ones is that they’re designed for white boards in front of a classroom so they’re big.  

If you have prolific builders around, there are also class kits with many many pieces, which allow for the assembly of large structures.

And finally, if you need the little thousandths chips, you can get them from McGraw Hill.   Since we don’t acknowledge thousandths of dollars and therefore can’t use money as an explanation aid beyond hundredths, it’s especially helpful to be able to see a physical illustration of that next mysterious decimal place. McGraw Hill also publishes a binder of activities to use with the blocks called Decimal Factory.