these are the only perfect squares
18:46
A questionable factorial problem
27:26
This open problem taught me what topology is
19:14
The strange cousin of the complex numbers -- the dual numbers.
21:25
one of the most beautiful techniques
22:59
The Dome Paradox: A Loophole in Newton's Laws
21:05
Why is there no equation for the perimeter of an ellipse‽
16:39
Way Bigger Than Graham's Number (Goodstein Sequence) - Numberphile
15:53