I'm a huge montessori fan and I try really hard to supplement our WAVA curriculum (which can sometimes be very 2 dimensional and dry) with lots and lots of montessori work.
My 6yo has been asking me lots of questions that would indicate some confusion about the decimal system and place value beyond the "tens place". So I put together some very simple activities to help out with that.
We made the place value cards (copies can be found at http://www.jmjpublishing.com/ once they get their site back up). She recognized those cards from her days at montessori and caught on VERY quickly to the concept of 100s and 1000s.
And then I put together a 1000s chain and helped her count all the way up to 1000.
Too bad my printer was almost out of ink and the arrows aren't so pretty. But she enjoyed this hands look at place value. The chain is very big, obviously. We did this work on our living room floor and she had a good time manipulating and configuring that big long chain. It took me 2 nights to make the chain from pony beads on plastic string. The red beads break up the groups of tens. I believe the real thousands chain is gold. But I couldn't find golden pony beads. So we decided that black and red would suit us just fine.