13．直接写出得数．
| 450÷9= | 560÷40= | 52×30= | 4500÷50= |
| 30×70= | 240÷80= | 40×25= | 250×4= |
| 500×5= | 780÷30= | 17×40= | 4500÷50= |
| 250×4= | 570÷3= | 570÷3= | 17×40= |
| 500×5= | 780÷30= | 323÷51≈ | 109×42≈ |
8．直接写得数．
0 160856 160864 160870 160874 160880 160882 160886 160892 160894 160900 160906 160910 160912 160916 160922 160924 160930 160934 160936 160940 160942 160946 160948 160950 160951 160952 160954 160955 160956 160958 160960 160964 160966 160970 160972 160976 160982 160984 160990 160994 160996 161000 161006 161012 161014 161020 161024 161026 161032 161036 161042 161050 199269
| 310-201= | 250×400= | 5400÷90= |
| $\frac{1}{5}+\frac{2}{5}$= | $1-\frac{5}{6}$= | 101×90-90= |