implemet the matlab help Takagi Sugeno example in fis

hi,i want to implement Takagi Sugeno model in matlab using FIS ,how can i set this rule:"if x is large and y is small, then z=x+y+2" of course i can add " If (x is large) and (y is small) then (Z is '...') " but i cannot add "x+y+2" ,how can i do it?

thanks so much