>none of us can multiply two arbitrary integers in our heads. So we are definitely not running 
   >the general algorithm. Most of us have the multiplication table memorized, which covers all 
   >multiplications up to 100. We might also have some simple heuristics stored that can multiply 
   >any X by 10, 100, or 1000; any X by 0, 1, or -1; multiplications that don’t require carry; 
   >etc. For everything else, we use a calculator.

I am confused whether the point being made is

(a) that no human being can multiply two random five digit integers without a calculator, or;

(b) that no human being can do it in our heads because we need external working storage such as paper, or;

(c) that the post is satire.