I clearly remember that eight grade math was algebra: basic stuff with polynomials like multiplying (2x + 1)(3x + 4), or dividing single terms like 4x^2y/2xy = 2x.

And that was likely behind where I would have been had I not immigrated to Canada from Europe, where I had been into basic one-variable linear equation solving by the end of fourth grade, plus other topics like sets. For instance we used a kind of set partitioning method to convert numbers into binary.

When I came to Canada in the fifth grade, the teacher took me to a room and probed me on various arithmetic of increasing difficulty. She was blown away that I could do long division of like a five digit number by a three dight number, either leaving it with a remainder, or else continuing into the fraction.