1.3x+2.7x=0.28
10-4x=8
5×3.2+2x=24
1.7×0.25×40
12.5×3.7×1.6
3.6×0.2×5
2.05×8.4= 14.75÷5.9= 5.7÷2.6≈(得数保留两位小数)