题目内容
能简算的用简便方法计算．
÷（
-0.2）
×（7.2+
）-
÷
[2.5-（
+0.15）÷0.6]×
（
+
）×8+
．
| 4 |
| 9 |
| 5 |
| 6 |
| 19 |
| 25 |
| 4 |
| 5 |
| 17 |
| 25 |
| 1 |
| 8 |
[2.5-（
| 17 |
| 20 |
| 2 |
| 5 |
| 5 |
| 8 |
| 1 |
| 27 |
| 19 |
| 27 |
①
÷（
-0.2）
=
÷（
-
）
=
÷
=
；
②
×（7.2+
）-
÷
=
×（
+
）-
÷
=
×8-
÷
=
×8-
×8
=（
-
）×8
=
×8
=
；
③[2.5-（
+0.15）÷0.6]×
=[2.5-（0.85+0.15）÷0.6]×0.4
=[2.5-1÷0.6]×0.4
=（2.5-
）×0.4
=2.5×0.4-
×0.4
=1-
=
；
④（
+
）×8+
=
×8+
×8+
=5+
+
=5+（
+
）
=5+1
=6．
| 4 |
| 9 |
| 5 |
| 6 |
=
| 4 |
| 9 |
| 5 |
| 6 |
| 1 |
| 5 |
=
| 4 |
| 9 |
| 19 |
| 30 |
=
| 40 |
| 57 |
②
| 19 |
| 25 |
| 4 |
| 5 |
| 17 |
| 25 |
| 1 |
| 8 |
=
| 19 |
| 25 |
| 36 |
| 5 |
| 4 |
| 5 |
| 17 |
| 25 |
| 1 |
| 8 |
=
| 19 |
| 25 |
| 17 |
| 25 |
| 1 |
| 8 |
=
| 19 |
| 25 |
| 17 |
| 25 |
=（
| 19 |
| 25 |
| 17 |
| 25 |
=
| 2 |
| 25 |
=
| 16 |
| 25 |
③[2.5-（
| 17 |
| 20 |
| 2 |
| 5 |
=[2.5-（0.85+0.15）÷0.6]×0.4
=[2.5-1÷0.6]×0.4
=（2.5-
| 5 |
| 3 |
=2.5×0.4-
| 5 |
| 3 |
=1-
| 2 |
| 3 |
=
| 1 |
| 3 |
④（
| 5 |
| 8 |
| 1 |
| 27 |
| 19 |
| 27 |
=
| 5 |
| 8 |
| 1 |
| 27 |
| 19 |
| 27 |
=5+
| 8 |
| 27 |
| 19 |
| 27 |
=5+（
| 8 |
| 27 |
| 19 |
| 27 |
=5+1
=6．
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