5千米8米=千米 3.5平方米=平方分米
0.180.108 2.12.10 3.2×1.023.2×0.98
7.8×0.57.8+0.5 0.9×0.720.9 0.89×272.7
0.46×39= 4.6×0.039=
4.6×=1.794 ×0.39=0.1794