15．口算．
0 162415 162423 162429 162433 162439 162441 162445 162451 162453 162459 162465 162469 162471 162475 162481 162483 162489 162493 162495 162499 162501 162505 162507 162509 162510 162511 162513 162514 162515 162517 162519 162523 162525 162529 162531 162535 162541 162543 162549 162553 162555 162559 162565 162571 162573 162579 162583 162585 162591 162595 162601 162609 199269
| 0.2×0.6= | 0.52÷52= | 3.6+4.4= | 3.4×0.2= |
| 7.8÷6= | 7.5÷0.3= | 0.42×3= | 0.99×0.1= |
| 1.8÷0.03= | 1÷4= | 3.72×4.4+5.6×3.72= | 3.5×3+3.5×7= |