The whole thing is worthwhile (it's less than a half hour), but here are some segments to pay attention to:
- How it works: c. 6:15-8:53: the sensorimotor basics. If you want to think about the "extended" mind, you have to start here.
- Mental calculation: c. 12:35-13:23: people can do sorobon calculations without actually having a sorobon. They do the calculations mentally, though they may move their fingers over an imaginary sorobon.
- Divination: 16:23-17:00: In the old days math was used more for divination than for solving practical problems.