7．估一估
| 21÷4≈ | 49÷8≈ | 121÷4≈ | 252÷5≈ |
| 183÷6≈ | 364÷9≈ | 482÷8≈ | 628÷9≈ |
4．算一算
| 96÷8= | 225÷2= | 98÷3= |
| 52×3= | 672÷6= | 538-257= |
| 483+579= | 437÷3= | 657÷5= |
3．口算．
0 160263 160271 160277 160281 160287 160289 160293 160299 160301 160307 160313 160317 160319 160323 160329 160331 160337 160341 160343 160347 160349 160353 160355 160357 160358 160359 160361 160362 160363 160365 160367 160371 160373 160377 160379 160383 160389 160391 160397 160401 160403 160407 160413 160419 160421 160427 160431 160433 160439 160443 160449 160457 199269
| 12×3= | 21×30= | 36×5= | 3.8+1.2= |
| 0.5+1.7= | 43×30= | 66×20= | 5.1-4.5= |
| 144÷2= | 60-12×5= | 91-27×3= | 17×66×0= |
| 72÷8×4= |
