What level math is she on? I found math boring until I took Algebra, same with DS16. All math is not equal I find "arithmetic" very boring and tedious. I don't have a lot of good suggestions other than those above. But something you said hit a bell me with me.
My DS16 is also very good at math, picks up new concepts quickly and test well. But it has always taken him a lot longer to do math homework than the other kids in his gifted program making math frustrating. I didn't really understand what was going on until I got DS tested last summer. DS has much lower low processing & working memory but very gifted at Perceptual Reasoning. Therefore explaining why he picks up the material easy but gets bogged down in hours of homework. Therefore you might want a math program that doesn't include large amounts of practice.