This is a set of 28 scales, one for each of the 28 CCSS Math Standards. These are 0-4 scales, with 3 being the proficient level of mastering the standard. I have each of these 28 scales listed for sale individually in my store. However, by purchasing the entire set at once, you save 50%! :) That's the equivalent of paying only $1.00 for each standard's scale. :) Please check out my numerous other scales (other grades and subjects) as well.