S-T, I'm not sure about this, but looking at the CTY catalog this morning, it appear they use the Thinkwell courses. I have no idea if they're any good, but I see them mentioned a lot. Would that help? I'm not sure if CTY allows non-US students, but it's online and appears to be the same thing. This is the course listing:
www.cty.jhu.edu/cde/courses.html You can contact them and ask. I am torn on all of these CTY courses. They are all existing courses, but they add the quizzes, tests, and tutors and they end up being very expensive.
Thinkwell is also available now on Homeschool Buyers Co-op:
https://www.homeschoolbuyersco-op.org/index.php?option=com_epp_offer&Itemid=576
