Absolutely, our issue was really with class sizes here. My third grader learned fractions, division, and some basic algebra (order of operations) over the summer. The class is still working on multiplication, so we're working at home to challenge him. My Kindergardener was in a class of 26, and it was just crazy, and too much for him to handle. It doesn't help that both boys inherited my ADHD, and the youngest has sensory processing issues on top of that. He easily gets over stimulated very easily, and was in hell going to school every day. Now he's in a class of 9 students, they finished thea kindergarden curriculum at Christmas, and moved on to the first grade curriculum. Plus they get two recess periods a day (which helps burn off that excess energy), Mandarin, Spanish, Art, Music, all of the subjects being cut or taken out of public school.
Does writing that check suck? Absolutely, but it's worth every penny to know the boys are happy, and being set up for success.