Students are provided instruction in less time than is typical (e.g., completing a one-year course in a semester or completing 3 years of middle school in two years). The time saved always results in advanced grade placement.
Or
Skipping a grade.
I'm doing geometrey currently which is a 10th or 11th grade class(depending on school). I learned basic triganometry this year which is sine, cosine, tangent, inverse-sine, inverse-cosing, and cotanget.
Some other people that telescope with me are Reese and Paige Sporrer & Lia Trone. You can telescope by talking to your teachers and higher up in the distric. They may have you take a test to see if yu are really able and ready to skip a grade.