0.49×0.22+258×0.0649＋5.3×6.49+64.9×0.19
=0.49×0.22+2.58×100×0.0649＋5.3×6.49+6.49×10×0.19
=0.49×0.22+2.58×6.49＋5.3×6.49+6.49×1.9
=0.49×0.22+6.49（2.58＋5.3+1.9）
=0.49×0.22+6.49×9.78
=0.1078+63.4722
=63.58
或
6.49×0.22+258×0.0649＋5.3×6.49+64.9×0.19
=6.49×0.22+2.58×100×0.0649＋5.3×6.49+6.49×10×0.19
=6.49×0.22+2.58×6.49＋5.3×6.49+6.49×1.9
=6.49（0.22+2.58＋5.3+1.9）
=6.49×10
=64.9