You've received excellent advice above - I'll just add a few thoughts. First and foremost, I agree with everyone who's noted that as long as your dds are keeping up in school, there's really no need to supplement math at home unless *they* are wanting to.
So, there has been lots of talk here on the forum about how public schools do a crummy job of teaching math.
So, I am appealing to you math people out there (I am so not a math person - I am in the arts)to help me figure out how to get my girls well educated in math.
Your girls are both bright girls - chances are they will get well educated in math without any help at all! Even if they have one or two or even three+ years of not-so-great math teachers and not-so-great curriculum. Please know I'm not making light of your concerns, but also know that I'm speaking from the perspective of a person with a degree in math and a career in a science field.
There are two things I've seen happen with math education over the past 20+ years - the first is a ton of re-working the how-to-teach math at the elementary school level, much of which has apparently not proved to be all that successful. That *doesn't* mean that smart kids can't still learn math (and learn to love it). It does mean you'll read a lot of not-so-great math curriculum discussions online. Try not to let those get you worried.
Second trend I've noticed - there's a bit of a trend to try to get kids "ahead" (accelerated) in secondary math in much larger numbers. We live in a world of achievers who want their children to achieve, and we have a lot of kids who are capable of higher level math in lower grades. The gotcha is that it feels (jmo) that one easy way of helping everyone feel like there child is getting acceleration and challenge and yadayada is by accelerating in math, simply because math is quantifiable and easy to benchmark acceleration. So it's easy to get caught up in the thought process that your student *needs* to be ahead - when really they don't. Instead of worrying about getting a child subject-accelerated as far as possible in math just for the sake of being accelerated in math, I'd instead look at where they are in science. Are they on an accelerated track? What types of science do you think they'll be ready for and interested in during which years in high school - and then make a math plan from there. Some types of science classes will require calculus credit or concurrent enrollment. Some will require other (lower) levels of math achievement. Some won't require much math at all. If your child is naturally driven to learn more and inspired by math, let them take the lead and get them placed where they need to be. If your child is bright, doing well in school etc, but not tearing down walls begging to do more math, get them in a track that will accomplish what they need to get them able to enroll in the science classes you're predicting they'll want to take. If your child is a great student and a high ability student but just really isn't all that interested in math, don't push it.
One of the things that I've seen (in my life and others) is that not all people were born to love math and some people will never ever even like it. We try really hard as a society to make math both interesting and appealing thinking that will prevent people from becoming math-phobic or not successful at math. Of the people I know who really like math, the discovery of their love of math often comes not in elementary school or even in middle school, but when they have the first applied course where they truly get the *it* - how math explains the world.
That happens earlier for some than for others, and sometimes it never happens - and all of it's ok. The one thing that I've seen that for sure doesn't work is trying to make kids study extra math when they aren't enjoying it. Doesn't work any better for math than anything else.
Hang in there - you're doing a great job of paying attention to your dds' needs and advocating for them. They'll be ok in math - really!
polarbear