5．口算：
0 156323 156331 156337 156341 156347 156349 156353 156359 156361 156367 156373 156377 156379 156383 156389 156391 156397 156401 156403 156407 156409 156413 156415 156417 156418 156419 156421 156422 156423 156425 156427 156431 156433 156437 156439 156443 156449 156451 156457 156461 156463 156467 156473 156479 156481 156487 156491 156493 156499 156503 156509 156517 199269
| 720÷24= | 9×80= | 80÷16= | 140×5= | 76-19= |
| 42÷2= | 1000÷20= | 880÷80= | 75×4÷4= | 440-12-12= |
