I have a ploblem about fomulas in revit quantities. as a attach image, i wan fomulars thk of duct, max(with,hight)>=450 is 0.8 thk, max(with,hight)>=900 is 0.9 thk, max(with,hight)<1800 is 1.2 thk, max(with,hight)>=1800 is 1.6 thk and max(with,hight)>450 is 0.6 thk.

ples help me, thanks all.