Does anyone notice how when they first learned to drive a car, they had to really work on clutch & gear coordination, parking, hill starts etc...?
I also noticed that as my cars progressed they got easier and easier to drive. Not because of my practice, but because of power steering, AWD, ABS, rear camera, ect ect ect.
Use a calculalor if you must. Use a wizz wheel if you must. Use your brain if you must.
Whatever you do. Do not get caught up in 15th century training methods.