Complex sentence: An obsessive overachiever, Lisa is able to instantly perform complex mathematical calculations mentally, keeps a detailed life-plan, and not only frequently brags about her SAT scores but goes so far as to retake the exam well out of college.
Split into simpler sentences: An obsessive overachiever, Lisa can instantly perform complex mathematical calculations and keeps a detailed life-plan. She frequently brags about her SAT scores and retakes the exam well out of college.