Superhero Triangles - Numberphile
12:33
Pascal's Triangle - Numberphile
27:31
Divisibility Tricks - Numberphile
17:47
Heron's formula (example and proof)
16:40
A Surprising Pi and 5 - Numberphile
19:29
The mathematically impossible ball that shouldn’t exist.
25:22
What Lies Above Pascal's Triangle?
13:25
Impossible Squares - Numberphile
20:19