Complex sentence: While at Battle School, they are taught academic subjects, including especially a heavy grounding in mathematics and science, a setup for work in space; for instance, Card describes Ender as learning trigonometry, which in the United States is not taught until high school.
Split into simpler sentences: While at Battle School, they are taught academic subjects; especially a heavy grounding in mathematics and science, a setup for work in space. For instance, Card describes Ender as learning trigonometry which, in the United States, is not taught until high school.