简便计算 1-1/6+1/42+1/56+1/72+1/90 = = = =简便计算 1-1/6+1/42+1/56+1/72+1_数学解答

简便计算 1-1/6+1/42+1/56+1/72+1/90 = = = =
简便计算 1-1/6+1/42+1/56+1/72+1/90
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人气：488 ℃　时间：2019-10-24 10:10:04

解答

1-1/6+1/42+1/56+1/72+1/90
=1-1/6+（1/6-1/7）+（1/7-1/8）+（1/8-1/9）+（1/9-1/10）
=1-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10
=1-1/10
=9/10