Learn to use the abacus(soroban), the Japanese way - Part 2

We are doing addition and subtraction by making use of the complementary numbers. This will be continued on part 3 of the soroban series.
9:43 reasoning behind the specific order of operation
3:12 addition using complementary numbers w.r.t. 5
4:48 subtraction using complementary numbers w.r.t. 5
6:30 addition using complementary numbers w.r.t. 10
8:09 subtraction using complementary numbers w.r.t. 10
/ @theoremofbeethoven
The video is created with Theorem of Beethoven's version of Manim.
/ @3blue1brown
Creator of Manim.
www.jahirulamin.com/
Hand model from Amin's tutorial.
Thank you to everyone above who have shared their knowledge and software to the whole world.
Background music played on a Casio digital piano.