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9*(1-2/5÷9/20﹚÷3/20-1又3/7

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/10 12:19:34
9*(1-2/5÷9/20﹚÷3/20-1又3/7
1/5÷[﹙2/3+20%﹚*1/13]
8*3又1/7÷[1÷﹙3又1/5﹣2.95﹚]
9*(1-2/5÷9/20﹚÷3/20-1又3/7
=9*(1- 2/5 × 20/9)×(20/3) - 1又3/7
=9*(1- 8/9)×(20/3) - 1又3/7
=9*(1/9)×(20/3) - 1又3/7
=20/3 - 1又3/7
=7 - 1/3 - 1 - 3/7
=6 - 7/21 - 9/21
=6 - 16/21
=5又5/21
.
1/5÷[﹙2/3+20%﹚*1/13]
=1/5÷[(2/3 + 1/5)*1/13]
=1/5÷[(10/15 + 3/5)*1/13]
=1/5÷[(13/15)*(1/13)]
=1/5÷(1/15)
=1/5 ×15
=3
.
8*3又1/7÷[1÷﹙3又1/5﹣2.95﹚]
=8*3又1/7÷[1÷(3.2 - 3 +0.05)]
=8*3又1/7÷(1÷0.25)
=8*3又1/7 ÷4
=2*(3+ 1/7)
=6 + 2/7
=6又2/7