题目内容
用简便方法计算
3+1949×（
-
）+58×（
-
）-2007×（
+
）
3+1949×（
| 1 |
| 58 |
| 1 |
| 2007 |
| 1 |
| 1949 |
| 1 |
| 2007 |
| 1 |
| 1949 |
| 1 |
| 58 |
3+1949×（
-
）+58×（
-
）-2007×（
+
），
=
+
+
+
-
+
-
-
-
，
=58×（
+
-
）+1949×（
+
-
）-2007×（
+
-
），
=（58+1949-2007）×（
+
-
），
=0．
| 1 |
| 58 |
| 1 |
| 2007 |
| 1 |
| 1949 |
| 1 |
| 2007 |
| 1 |
| 1949 |
| 1 |
| 58 |
=
| 58 |
| 58 |
| 1949 |
| 1949 |
| 2007 |
| 2007 |
| 1949 |
| 58 |
| 1949 |
| 2007 |
| 58 |
| 1949 |
| 58 |
| 2007 |
| 2007 |
| 1949 |
| 2007 |
| 58 |
=58×（
| 1 |
| 58 |
| 1 |
| 1949 |
| 1 |
| 2007 |
| 1 |
| 58 |
| 1 |
| 1949 |
| 1 |
| 2007 |
| 1 |
| 58 |
| 1 |
| 1949 |
| 1 |
| 2007 |
=（58+1949-2007）×（
| 1 |
| 58 |
| 1 |
| 1949 |
| 1 |
| 2007 |
=0．
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