六年级数学!简便运算~~分数除法~~(2)10除于5/9+1/6X4(要用递等式~~~)===7/9除于11/5+2/9X5/11===(1/12+1/2-7/12)除于1/7===

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六年级数学!简便运算~~分数除法~~(2)10除于5/9+1/6X4(要用递等式~~~)===7/9除于11/5+2/9X5/11===(1/12+1/2-7/12)除于1/7===
六年级数学!简便运算~~分数除法~~(2)
10除于5/9+1/6X4(要用递等式~~~)
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7/9除于11/5+2/9X5/11
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(1/12+1/2-7/12)除于1/7
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六年级数学!简便运算~~分数除法~~(2)10除于5/9+1/6X4(要用递等式~~~)===7/9除于11/5+2/9X5/11===(1/12+1/2-7/12)除于1/7===
10除于5/9+1/6X4(要用递等式~)
= 10×9/5+4/6
= 18+2/3
= 18又2/3
7/9除于11/5+2/9X5/11
= 7/9×5/11+2/9×5/11
= (7/9+2/9)×5/11
= 1×5/11
=5/11
(1/12+1/2-7/12)除于1/7
= (1/12+1/2-7/12)×7
= 1/12×7+1/2×7-7/12×7
= 7/12+7/2-49/12
=3又1/2
(你这题中的-7/12应该是-1/12吧?)