Summer of Math Exposition

Repeated emphasis of the target audience and naming convention undermines the subject at hand and more than satisfactory explanations.

the video is showing a way of thinking, but never let the viewer try for them self an then let us try this method, nice way of thinking but I think the SoME is more about thinking and the video didn't really intrigued me

This is well-motivated and clear, but it is meant as a pedagogical tool for early high school, not directed at math enthusiasts. Also, as the creator mentions at the end of the video, the method he describes is not new - only not widely used.

Beautifully animated. Regarding words for 'un-add', my suggestion would be 'split'. Splitting a number into 2 parts intuitively feels like a additive split, rather than a multiplicative split or any other split, at least to me. All that said, while I could follow your un-add solutions, and they were much easier to follow in ones head than the system of equations, I am still a bit fuzzy about what the Un-Add method is. How exactly do you pick what to split and how to split it? If that choice is coming intuitively to a person, great. But otherwise, the system of linear equations may be easier since it does not need that insight.

I suggest getting a better microphone and using animations in your videos.

It was not for me

I like it. It has a similar feeling to the way East Asians are taught to solve algebraic equations before learning manipulation of variables though representations like a tape diagram. Much more intuitive for children to deal with in a transition to algebra. You might look at Cognitively Guided Instruction materials for a label of "unadding". They describe a variety of structures for addition and subtraction type problems. I think this would fall under "Part-part-whole".