For me, who needed structure, I most enjoyed the Saxon method of learning. It was heavy on problem sets and homework, but you retained what you learned because a part of each problem set was always designed to revisit past lessons. By the time it was test time, you could be fairly confident that you understood all of the material without additional studying.

Second favorite was in 6th grade where we were handed a bunch of color coded workbooks and told to go at it. I finished the entire grade's assignments by the end of the first 9 weeks, and I hated math. I was just competitive. In hindsight, it's probably why I was placed in the advanced clas when we were promoted to the next grade level. Because I finished all of that content before the end of 6th grade, too. I understood pre-algebra concepts because I had started writing programs on my dad's Ti 99/4a.