=4.4×28.6+(28.6+12.5)×5.6
=4.4×28.6+28.6×5.6+12.5×5.6
=(4.4+5.6)×28.6+12.5×8×0.7
=286+70=356
第二题类似,把28.8拆成（26.3+2.5）,以下相同