999.9*0.28-666.6*0.37
=111.1(9*0.28-6*0.37)
=111.1(18*0.24-6*0.37)
=111.1*6*(3*0.14-0.37)
=111.1*6(0.52-2*3.0.37）=666.6*0.15=99.99