Read this paragraph from The Adventures of Huckleberry Finn by Mark Twain. Well, three or four months run along, and it was well into the winter now. I had been to school most all the time and could spell and read and write just a little, and could say the multiplication table up to six times seven is thirty-five, and I don't reckon I could ever get any further than that if I was to live forever. I don't take no stock in mathematics, anyway.

What is the author’s purpose for including this paragraph?