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(10-7/55×1)+(9-7/55×1)+(8-7/55×1)+.+(1-7/55×1)怎么简算?
对不起,我打错了 应该是:(10-7/55×1)+(9-7/55×2)+(8-7/55×3)+......+(1-7/55×10)怎么简算?
人气:316 ℃ 时间:2020-03-26 06:35:40
解答
(10-7/55×1)+(9-7/55×1)+(8-7/55×1)+.+(1-7/55×1)
=(10+9+8+···1)-7/55×1×10
=(10+1)×10/2-14/11
=55-14/11
=55-1又3/11
=(54-1)+(1-3/11)
=53+8/11
=53又8/11看不懂。。。。。。。。。。。。把式子拆开看,每个括号前的整数分别相加,然后减去10个7/55×1。打错了 请你重新写一下把式子拆开看,每个括号前的整数分别相加,然后减去(1+2+3+···10)个7/55×1。(10-7/55×1)+(9-7/55×2)+(8-7/55×3)+......+(1-7/55×10)=(10+9+8+···1)-7/55×(1+2+3+···10)=(10+1)×10/2-7/55×(10+1)×10/2=55-7/55×55=55-7=48
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