These are not large numbers. When I was in college, we had some multiple choice answers that were simply designed to see if people were grasping the concepts and could “visualize” what a ballpark figure might be (micro numbers, macro numbers, etc.).
This is third grade. Not college. You don't teach nine year olds like eighteen year olds.
Of course, the kids gotta start somewhere; I still don't think that it is a good idea to teach that process early on.
"ballpark numbers" - like approximating at infinity in diffy Q