199.9乘199.9-200乘199.8

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收藏|2022/11/13 17:05

满意回答

2022/11/13 17:20

199.9x199.9-200x199.8=199.9x199.9-200x(199.9-0.1)=199.9x199.9-200x199.9+200x0.1=199.9x(199.9-200)+20=199.9x(-0.1)+20=-19.99+20=0.01

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其他回答(4)
  • =0.01 199.9×199.9=39960.01 200×199.8=39960 39960.01-39960=0.01
    回答于 2022/11/13 19:10
  • 199.9×199.9-200×199.8=199.9×199.9-(199.9+0.1)×199.8=199.9×199.9-199.9×199.8-0.1×199.8=199.9×(199.9-199.8)-19.98=199.9×0.1-19.98=19.99-19.98=0.01如果知道平方差公式:(a+b)(a-b)=a²-b²那么原式=199.9²-(199.9+0.1)×(199.9-0.1)=199.9²-(199.9²-0.1²)=0.1²=0.01
    回答于 2022/11/13 18:46
  • 199.9*199.9 - 200*199.8= (200*199.9-0.1*199.9)- (200*199.9-200*0.1)=-0.1*199.9 -(-200*0.1)=(200-199.9)*0.1=0.1*0.1=0.01;典型的数学行为
    回答于 2022/11/13 18:25
  • =199.9*199.9-(199.9+0.1)*(199.9-1)=199.9²-(199.9²-0.1²)=199.9²-199.9²+0.1²=0.01
    回答于 2022/11/13 17:53
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