Complex sentence: He is the founder of the Khan Academy, a free online education platform and a 501 (c) (3) organization with which he has produced over 6,500 video lessons teaching a wide spectrum of academic subjects, mainly focusing on mathematics and sciences.
Split into simpler sentences: He is the founder of the Khan Academy, a free online education platform and a 501 (c) (3) organization. Khan has produced over 6,500 video lessons teaching a wide spectrum of academic subjects, mainly focusing on mathematics and sciences.