Complex sentence: He later obtained a Master's degree in mathematics, and was hired as a teacher in 1966 at Butler University, where he worked for the next 40 years, teaching nearly every subject in the mathematics department.
Split into simpler sentences: He later obtained a Master's degree in mathematics, and was hired as a teacher in 1966 at Butler University. Over the next 40 years, he has taught nearly every subject in the mathematics department.