My son did sets at the beginning of Grade 3. Empty sets, subsets, adding sets.... etc.

I realize that EPGY is recommending getting 80% correct. Having worked on it, I actually think that is too low, at least for my son. At what seems to be an accurate placement, he scores about 90% overall. Higher in some areas, lower in others. To pass their final, you have to get 85% (I think. If not, 80%) . The student effectively gets two chances at answering the question, so at the first attempt 80% makes sense. But at the second time around, I think it needs to be higher. On the calendar/sessions area, you can replay the sessions and see how what percent your child is getting on the first and second attempt.