If you start roasting a 14-pound turkey at 375 F at 7 a.m. and need to feed 15 people — including three vegetarians, a vegan and two gluten intolerants — by 1 p.m., how many pounds of cranberries do you need if the stuffing is baked outside the bird and the pumpkin pie is cut into 11.75 equal wedges? Or am I the only cook who suffers flashbacks to grade school word problems every time I try to calculate the many mathematical angles of assembling Thanksgiving dinner? Fear not.