用简便方法计算.(要求写出简便过程)
| 15.3-7.28+4.7-2.72 | (24+ |
| 直接写出得数. 500-200=________; | 3000+600=________; | 35÷4=________; | 2000+80=________; |
| 36÷9=________; | 56÷6=________; | 450+160=________; | 9×7=________; |
| 54-45=________; | 710+90=________; | 89÷9=________; | 1200-1050=________. |
计算下面各题,怎么简便就怎样算
| ①9 | ②1.8× |
| ③(8 | ④2 |