Question: How can homeschooling be effective for intense subjects like calculus, physics, chemistry, and trigonometry?Answer: It takes a well-educated parent who has understanding of these topics to teach them. Alternatively a tutor may be employed. Either way it's much more effective than a classroom setting. The real question is, "How can someone teach intense subjects like calculus, physics and geometry to 30 or more people simultaneously?" Many high school-aged homeschoolers take classes at their community college. Larger cities oftentimes have homeschooling co-ops or classes where parents or other people who are very knowledgeable in a certain area (for example, are former math teachers or have a math degree) will teach a group of homeschoolers. Sometimes parents learn the material or give themselves a refresher course before they teach it to their children.