（1）(258-147)÷[(3112+4.375)÷1989]（2）[113×(4112-2.625)-412]÷335（3）2-613÷926-23+1835÷0.6×23（4）[213+(5.4-223)×123]÷689．-数学
| 18 |
| 35 |
| 2 |
| 3 |
=2-
| 4 |
| 3 |
| 2 |
| 3 |
| 18 |
| 35 |
| 5 |
| 3 |
| 2 |
| 3 |
=0+
| 4 |
| 7 |
=
| 4 |
| 7 |
（4）[2
| 1 |
| 3 |
| 2 |
| 3 |
| 2 |
| 3 |
| 8 |
| 9 |
=[2
| 1 |
| 3 |
| 2 |
| 5 |
| 2 |
| 3 |
| 2 |
| 3 |
| 8 |
| 9 |
=[2
| 1 |
| 3 |
| 41 |
| 15 |
| 5 |
| 3 |
| 62 |
| 9 |
=[2
| 1 |
| 3 |
| 41 |
| 9 |
