=2007+0.5×27+0.24×270+191.7
=2007+0.5×27+2.4×27+191.7
=2007+（0.5+2.4）×27+191.7
=2007+2.9×27+7.1×27
=2007+（2.9+7.1）×27
=2007+10×27
=2007+270
=2277