The problem sets are derived from 22 different skills/topics--at least 3 of which are beyond the Common Core (but typical of curricula before the Common Core's adoption).
FOUR worksheets are provided: one with 15 problems per skill; one with 12 per skill; one with 9 per skill and one with 6 per skill. You decide which is best for you.
SEVEN quizzes (all with 20 problems each) are provided: TWO at a level 2 (not too hard); TWO at levels 2 and 3 (harder); TWO at level 3; ONE at levels 3 and 4 (p