> I was stating (as a fact) where you learn it (at high school math classes). Interestingly your "fact" is false - from my experience. You'd need to specific c

> I was stating (as a fact) where you learn it (at high school math classes). Interestingly your "fact" is false - from my experience. You'd need to specific country where this high school is located, the year of the syllabus and possibly a region within a country. When I went to "high school" (we don't call it that) the syllabus differed by region. And we never studied cartesian products.