This "Big Think" talk by Terence Tao is worth the 90-minute investment. The first half hour or so is invaluable for everyone high-school-aged and above in summarizing the Big Ideas in mathematics (there was even an anecdote about Kepler that I never heard before). (1/3)
youtu.be/OOMx2BHHWtE?...
youtu.be
The world's greatest mathematician explains 6 essential concepts of math | Terence Tao
YouTube video by Big Think