Math standards

    I am a Canadian Teacher and I am very curious about math
    standards in the USA. I understand that there is a list of
    common core state standards that everyone needs to
    follow...have most states adopted this as is, or are there
    states that have added significantly to the common core?
    Our province is in the process of implementing new
    curriculum and that in turns gives us as teachers the
    opportunity to take a critical look at what we are working
    with and how we can improve our programs. As American
    teachers, what are your thoughts on the current core
    standards? Do you find them "workable?" Are there too many
    standards to meet? Not enough? Would love your feedback,
    esp in regards to the math curriculum. Thanks.