I doubt there are any states that don't currently have fractions in their curricula. The problem isn't standards, it's that large swathes of the country simply

I doubt there are any states that don't currently have fractions in their curricula. The problem isn't standards, it's that large swathes of the country simply don't care about educating their children, as indicated at a societal level by where tax revenue goes, and at the individual level by parental involvement in children's education. How to solve that short of charging people with neglect, I've got no idea.