I took the new section 4 last December and it had a fair amount of questions that would fit in the grading category. A few of the questions required basic calculations. Knowing the slope formula essential. It would also be good to know the proper placement of various types of SWM devices, contour orientation, and what the contour "shape" of different types of things looks like (ex. roads, curbs, paths, swales, berms, slabs etc.)
I studied grading using the CLARB sample exam questions, reviewing the old grading vignettes, and working through Landscape Grading by Valerie Aymer. I found the problems in Strom to be too complex for the drag and drop type questions on the exam. The CLARB sample exam is really your best resource for preparing for how the questions may be worded and graphically displayed.