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跪求平行线教育数学思维引导六年级第二本第一讲分数简算答案 会补充页数和题目【以下共三题

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跪求平行线教育数学思维引导六年级第二本第一讲分数简算答案 会补充页数和题目【以下共三题

我对不起回答问题的亲们的脖子... 会追加 越快越好哦! 感谢!
跪求平行线教育数学思维引导六年级第二本第一讲分数简算答案 会补充页数和题目【以下共三题
1.
(78.6-0.786×25+75%×21.4)÷15×1997
=[ 78.6-0.786×25+75%×(100-78.6)]÷15×1997
= (78.6-78.6%×25+75%×100-75%×78.6)÷15×1997
=﹙ 78.6- 78.6%×25 + 75- 75%×78.6﹚÷15×1997
=﹙ 78.6- 78.6%×25 + 75- 75×78.6%﹚÷15×1997
= [78.6- 78.6%×﹙25 + 75﹚﹢75]÷15×1997
=75÷15×1997
=5×1997
=9985
2.
﹙1+1/2+1/3+1/4﹚×﹙1/2+1/3+1/4+1/5﹚-﹙1+1/2+1/3+1/4+1/5﹚×﹙1/2+1/3+1/4﹚

=﹙1+1/2+1/3+1/4+1/5-1/5﹚×﹙1/2+1/3+1/4+1/5﹚-﹙1+1/2+1/3+1/4+1/5﹚×﹙1/2+1/3+1/4﹚

=﹙1+1/2+1/3+1/4+1/5﹚×﹙1/2+1/3+1/4+1/5﹚-1/5×﹙1/2+1/3+1/4+1/5﹚-﹙1+1/2+1/3+1/4+1/5﹚×﹙1/2+1/3+1/4﹚

=﹙1+1/2+1/3+1/4+1/5﹚× [﹙1/2+1/3+1/4+1/5﹚-﹙1/2+1/3+1/4﹚
]-1/5×﹙1/2+1/3+1/4+1/5﹚

=﹙1+1/2+1/3+1/4+1/5﹚× 1/5 - 1/5×﹙1/2+1/3+1/4+1/5﹚

=1/5
3.题目看的不是太清晰
思路同上
﹙1+0.23+0.34﹚×﹙0.23+0.34+0.65﹚-﹙1+0.23+0.34+0.65﹚×﹙0.23+0.34﹚
=﹙1+0.23+0.34 + 0.65 -0.65﹚×﹙0.23+0.34+0.65﹚-﹙1+0.23+0.34+0.65﹚×﹙0.23+0.34﹚
=﹙1+0.23+0.34 + 0.65 ﹚×﹙0.23+0.34+0.65﹚-0.65×﹙0.23+0.34+0.65﹚-﹙1+0.23+0.34+0.65﹚×﹙0.23+0.34﹚
=﹙1+0.23+0.34 + 0.65 ﹚×[﹙0.23+0.34+0.65﹚-﹙0.23+0.34﹚]-0.65×﹙0.23+0.34+0.65﹚
=﹙1+0.23+0.34 + 0.65 ﹚×0.65-0.65×﹙0.23+0.34+0.65﹚
=1×0.65 +﹙0.23+0.34+0.65﹚×0.65-0.65×﹙0.23+0.34+0.65﹚
=0.65
多做题,总结经验.不难的