Algebra-the part of mathematics in which letters and other general symbols are used to represent numbers and quantities in formulas and equations.
"I don't want to copy your homework," I replied, although I would have taken his algebra if he had offered."
Orbit
Orbit-the curved path of a celestial object or spacecraft around a star, planet, or moon, especially a periodic elliptical revolution.
"I saw on television where Dr. von Braun had given an interview and he said, in a crisp German accent, that if he got the go-ahead he could put a satellite into orbit within 30 days."