18．计算，能简算的要简算．
| 45×17+55×17 | 25×104 | 101×87-87 |
| 125×32×25 | 53.76-5.71-4.29 | 8.42-（2.42+1.56） |
17．直接写得数．
| 0.5+1.6= | 7.2-4= | 1+0.38= | 40÷1000= |
| 8-7.2= | 54÷3= | 2.91-0.7= | 0.63×10= |
| 0.56+0.4= | 1.25×100= | 90+0.9= | 6.7+25.3= |
| 0×340÷17= | 25×4+30= | 125×7×8= | 9.6-3.8-1.2= |
16．从10里面连续减去0.1，连续减（ ）次，结果是0．
0 157400 157408 157414 157418 157424 157426 157430 157436 157438 157444 157450 157454 157456 157460 157466 157468 157474 157478 157480 157484 157486 157490 157492 157494 157495 157496 157498 157499 157500 157502 157504 157508 157510 157514 157516 157520 157526 157528 157534 157538 157540 157544 157550 157556 157558 157564 157568 157570 157576 157580 157586 157594 199269
| A． | 100 | B． | 10 | C． | 1000 |