I am honestly disappointed by this "curriculum" (same for the other grade levels). The teacher manual is just an 'updated' version of a previous book titled "Challenging Common Core Math Lessons" - I already have all of those books, so my purchase of these 'updated' grade levels cost me over $400! If you have "Challenging Common Core Math Lessons", don't waste your money on this.
The student workbooks are not even truly designed for a student to use as-is. For example, the workbooks (which are just copies of the activities in the teacher manual), contain task cards or memory cards to cut out - but the student can't cut them out; there is almost always something on the other side of the page! The cards for all of the activities should have been printed and sent with the teacher materials.
The activities and practice problems are good for gifted students, but this could have been so much better. I wish this were a truly new product rather than a repackaging of an old one.