Using datetime:
A = [6 9 10 1
7 15 8 15
11 15 12 4];
t = datetime(zeros(size(A,1),2),A(:,[1,3]),A(:,[2,4]))
res = duration(t(:,2)-t(:,1),'Format','d')
res =
3×1 duration array
114 days
31 days
19 days
