3.8乘以9.9还有高招吗?

3.8×9.9 =3.8×10-3.8×0.1 =4×10-0.2×10-3.8×0.1 =4×10-0.2×10-4×0.1+0.2×0.1 =40-2-0.4+0.02 =37.62