735 + 243 – 135 – 143   =
                                                (735 – 135) + (243 – 143)  =
                                                         600       +       100         =     700   

12633

\(=\frac{2015\left(2006+1\right)-1}{2004+2005.2006}=\frac{2005.2006+2005-1}{2004+2005.2006}=1\)