9．计算，带*验算
| *751-206= | *720-170= | *630+250= |
| 1000-472= | 124×13= | 502-366= |
8．口算．
0 160956 160964 160970 160974 160980 160982 160986 160992 160994 161000 161006 161010 161012 161016 161022 161024 161030 161034 161036 161040 161042 161046 161048 161050 161051 161052 161054 161055 161056 161058 161060 161064 161066 161070 161072 161076 161082 161084 161090 161094 161096 161100 161106 161112 161114 161120 161124 161126 161132 161136 161142 161150 199269
| 370+450= | 607-489= | 45÷9= | 56÷7= |
| 9×8= | 204+447≈ | 106+438≈ | 244-123≈ |