\(-2003+\left(-21+75+2003\right)\\ =-2003-21+75+2003\\ =\left(-2003+2003\right)+\left(75-21\right)\\ =0+54\\ =54\)
\(1125-\left(374+1125\right)+\left(-65+374\right)\\ =1125-374-1125-65+374\\ =\left(1125-1125\right)+\left(-374+374\right)-65\\ =0+0-65\\ =0-65\\ =-65\)