What subject in education is the most valuable in your opinion?

“Reading, writing, and arithmetic” so the saying goes. These are the principle pillars of education. My father grew up quite literally in the Dust Bowl and learned little else, until he got to the army. He credits his mathematical prowess with his entry into the Army Air Corp, and his subsequent successes in life.

In my opinion, reading is more fundamental. Without it, one can hardly do anything at all. Whereas with it, one can read the math textbooks to learn those concepts.

In your opinion, is one of these subjects the most important, or is it one not listed here?