Are there any fun math sites that can be used to teach/assess knowledge of Common Core standards? Our AG teacher recommends that our daughter get into a single subject acceleration math class, but first our daughter must pass a test in May to show that she knows much of her grade and the next. I would like to know just what our daughter does know.
Thanks!

My DS8 enjoys IXL which looks like it aligns with common core. As he's literally tried hundreds of math sites and apps and still uses IXL might be a good testament.

DS brought home log-in info from his school for Adapted Mind Math and so far I like it better than ixl. With ixl they have to do a ridiculous number of problems before they finish a lesson, but with Adapted Mind Math it "adapts" the number of problems based on whether they are answering correctly or not and they may only have to do 5 or 10 problems for a standard before mastering it. There are also video lessons on Adapted Mind, which ixl doesn't have. It's about the same cost as ixl. I think it only goes through grade 5 or 6 standards.

DD really likes Khan Academy, which goes from around grade 3 to very advanced math (and best of all it is FREE).

I don't know that I would classify either of those sites as "fun". With both of them kids can earn badges which my kids enjoy (7 and 8 yo).

DS really liked Dreambox (we did a free trial), but I'm not sure how closely it aligns with standards.

My daughter loves Khan Academy as well. I have to tear her away!! I just don't know what level she is doing there - she just rummages around and does all kinds of items. I know that the site states that it will be more connected to Common Core this summer, but right now it just lists those standards on another page.

Khan has a Common Core area for K-12. They do not have much yet. But they say on the site that by summer 2014 they will have updated with most CC standards materials and videos.
I was looking around at it the other day and found many videos and quizes for my son. He seemed to enjoy it.

Math Mammoth and Singapore Math are curriculums, not what you're asking for, but they have placement tests and are aligned with the common core. It would be a quick way to look for gaps. TAKS (Texas standardized test) is
also online, or they have their old tests online. You could ask her to take the test orally while you sit there, then you'll know what she knows and what she doesn't know.

You can look on youtube for any math lesson she doesn't know. Math mammoth and khan academy both have a lot of videos on youtube. There's a lot of videos for almost anything you look up.

eta: the common core math standards are also online so you can look up her grade level to get an idea.