## 06 February 2020

### Interesting "Russian multiplication"

1. I could not imagine teaching this to middle school students.

Amazingly, it does work.

2. my interest was piqued by how to find the binary of any decimal number (at 5:55 https://youtu.be/HJ_PP5rqLg0?t=356) until i realized that was previously covered in my freshman computer science classes! a good refresher, none the less.

I-)

3. I'm not sure I see the practical value of this way of multiplication. It's nice with 9x13, but when you have to go 1356x4322, it kinda falls apart as a lot of work.

1. Well the advantage to ancient peoples was that you can do this without the Hindu–Arabic numeral system. Our standard multiplication algorithm is not possible without the positional numbers (e.g. 15 is always greater than 5. None of this nonsense where V is greater than IV) and the zero provided by that system.

If you can multiply four digit numbers you could impress the hell out of Pythagorus because multiplying using roman numerals and other similar tally mark systems is exceedingly difficult.

4. Mind... blown... Thank you!