计算下面各题，（能简算的要简算）45-(311-15)518+320-29811+(67+311)56+720-320+1638+56+13517+78-417+18．-数学
（2）
| 5 |
| 18 |
| 3 |
| 20 |
| 2 |
| 9 |
=
| 50 |
| 180 |
| 27 |
| 180 |
| 40 |
| 180 |
=
| 37 |
| 180 |
（3）
| 8 |
| 11 |
| 6 |
| 7 |
| 3 |
| 11 |
=
| 8 |
| 11 |
| 6 |
| 7 |
| 3 |
| 11 |
=（
| 8 |
| 11 |
| 3 |
| 11 |
| 6 |
| 7 |
=1+
| 6 |
| 7 |
=
| 6 |
| 7 |
（4）
| 5 |
| 6 |
| 7 |
| 20 |
| 3 |
| 20 |
| 1 |
| 6 |
=（
| 5 |
| 6 |
| 1 |
| 6 |
| 7 |
| 20 |
| 3 |
| 20 |
=1+
| 1 |
| 5 |
=1
| 1 |
| 5 |
（5）
| 3 |
| 8 |
| 5 |
| 6 |
