\(1980+1985.1986-\left(1985.1987-1\right)=1980+1985.1986-1985.1987+1=1981+1985.\left(1986-1987\right)=1981-1985=-4< 0\)
\(\Rightarrow1980+1985.1986< 1985.1987-1\)
\(\Rightarrow\dfrac{1980+1985.1986}{1980+1985.1986}< \dfrac{1985.1987-1}{1980+1985.1986}\)
\(\Rightarrow A>1\)