题目内容
（1+
+
+
）×（
+
+
+
）-（1+
+
+
+
）×（
+
+
）
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分析：先将式子变形为（1+
+
+
）×（
+
+
）+（1+
+
+
）×
-（1+
+
+
）×（
+
+
）+
×（
+
+
），再抵消后运用乘法分配律简便计算．
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解答：解：（1+
+
+
）×（
+
+
+
）-（1+
+
+
+
）×（
+
+
），
=（1+
+
+
）×（
+
+
）+（1+
+
+
）×
-（1+
+
+
）×（
+
+
）-
×（
+
+
），
=（1+
+
+
）×
-
×（
+
+
），
=（1+
+
+
-
-
-
）×
，
=1×
，
=
．
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=（1+
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=（1+
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=（1+
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=1×
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=
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点评：考查了分数的巧算，关键是灵活运用乘法分配律，同时注意整体思想和抵消法的运用．
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