This is Part II of II covering conduit (raceway) fill. This video focuses on examples and calculations, whereas Part I covered the Code requirements.
There is a mistake in the last example. The total area of four 10 AWG THHN conductors is 0.0211*4=0.0844 in^2. The allowable space of a trade size 1 EMT is 0.346 in^2. The remaining allowable space of the raceway is 0.346-0.0844=0.2616 in^2. Therefore 0.2616/0.0133=19,66. Therefore 19 12 AWG THHN conductors can be added.