It's been a long time since I've looked at it, so I don't remember how early the "early" is on it, but my dds both loved Dreambox (
www.dreambox.com). It's online, and we had no problems running it on a Mac using Safari. The downside is it's a subscription service, but I think it wasn't terribly expensive.
My 4th grade dd's class is also using math-whiz (you can google math-whiz to get the website) - it's got some fun/games built into it too, and I think the website says it starts at Kindergarten level, so it might be another one to look at if you think your ds is ready for K-level math
polarbear
