After having an hour-long conversation with a concerned mother from India about her children's education in math, I checked around and have added a few more books to the list.
One of the things to remember in US Math k12 education, is that instead of learning math as a recipe, children learn it conceptually (a little bit - I wish it were more, actually). Consequently in the U.S. we don't cover as much territory in math, however the students who are interested and talented are able to go in greater depth.
Many teachers, particularly of Honors students (or Gifted and Talented, Enhanced Learning Programs, etc.) test to see where the limits of understanding are. Consequently, a score of 72% doesn't usually mean that the student can only follow the recipe 3/4 of the time; it means that the student was given an exam with questions on it of varying difficulty and earned 3/4 of the possible points. It's entirely likely that only half the questions were "cook book," and the student got 100% on those! It's also probable that one or two questions were quite difficult and possibly incorporated concepts that the student hasn't officially learned.