That’s a pretty good analogy, the 5 + 20 example.

By using abstract symbols, it encourages one to skip the internal verbalization and go straight to the concept. Pretty neat.

But in the article, they use symbols that I don’t have on my keyboard. I guess one would learn the combination for such symbols and become fluent to the point that it didn’t matter. For example, I don’t think of the individual letters when I’m typing.

Although my highschool typing class strongly encouraged doing so. I believe that was more for maintaining a rhythm, however.