作业帮79*69/80怎样简便算
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79*69/80怎样简便算
79*69/80怎样简便算
79*69/80怎样简便算
79*69/80
=(80-1)*69/80
=80*69/80-1*69/80
=69-69/80
=68又11/80
79*69/80
=（80-1）×69/80
=80×69/80-1×69/80
=69-69/80
=68又11/80
呵呵，把79看成（80-1）就好办了~再把括号拆开，这就是这道题的简便…………那9/20*101*9/20？原题 =0.45×0.45×101 =0.45×（100+1）×0.45 =（0.45×100+0.45×1）×0.45 ...
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79*69/80
=（80-1）×69/80
=80×69/80-1×69/80
=69-69/80
=68又11/80
呵呵，把79看成（80-1）就好办了~再把括号拆开，这就是这道题的简便…………
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=(80-1)*69/80
=80*69/80-1*69/80=69-69/80=68又11/80