=1+1/2-(1/2+1/3)+(1/3+1/4)-(1/4+1/5)+(1/5+1/6)-(1/6+1/7)+(1/7+1/8)-(1/8+1/9)
=1+1/2-1/2-1/3+1/3+1/4-1/4-1/5+1/5+1/6-1/6-1/7+1/7+1/8-1/8-1/9
=1-1/9
=8/9本回答被提问者和网友采纳
=1+1/2-1/2-1/3+1/3+1/4-1/4-1/5+1/5+1/6-1/6-1/7+1/7+1/8-1/8-1/9
=1-1/9
=8/9
1+1\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72 不通分,如何简便计算
=1+1\/2-1\/2-1\/3+1\/3+1\/4-1\/4-1\/5+1\/5+1\/6-1\/6-1\/7+1\/7+1\/8-1\/8-1\/9 =1-1\/9 =8\/9
1+1\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72 =
1+1\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72 =1+1\/2-(1\/2+1\/3)+(1\/3+1\/4)-(1\/4+1\/5)+(1\/5+1\/6)-(1\/6+1\/7)+(1\/7+1\/8)-17(1\/8+1\/9)=1-1\/9 =8\/9
1+1\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56=? 求简便计算
1+1\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56 =1+1\/2-1\/2-1\/3+1\/3+1\/4-1\/4-1\/5+1\/5+1\/6-1\/6-1\/7+1\/7+1\/8 =1+(1\/2-1\/2)-(1\/3-1\/3)+(1\/4-1\/4)-(1\/5-1\/5)+(1\/6-1\/6)-(1\/7-1\/7)+1\/8 =1+1\/8 =9\/8 ...
1又1\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56 怎么简便运算
1又1\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56 =1+1\/2-(1\/2+1\/3)+(1\/3+1\/4)-(1\/4+1\/5)+(1\/5+1\/6)-(1\/6+1\/7)+(1\/7+1\/8)=1+1\/2-1\/2-1\/3+1\/3+1\/4-1\/4-1\/5+1\/5+1\/6-1\/6-1\/7+1\/7+1\/8 =1+1\/8 =1又1\/8 ...
1又1\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56 怎么简便运算
1又1\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56 =1又6\/12+7\/12-10\/12-(27\/60-22\/60)-(52\/168-45\/168)=1又3\/12-5\/60-7\/168 =1又3\/12-1\/12-7\/168 =1又2\/12-7\/168 =1又28\/168-7\/168 =1又21\/168 =1又1\/8 ...
1加1\/2减5\/6加7\/12减9\/20加11\/30减13\/42加15\/56减17\/72。等于多少?
5\/6=1\/2+1\/3,7\/12=1\/3+1\/4,同理可得后面的9\/20,11\/30,13\/42,15\/56,17\/72.所以原式=1+1\/2-(1\/2+1\/3)+1\/3+1\/4……-(1\/6+1\/7)+1\/7+1\/8-(1\/8+1\/9)=1-1\/9=8\/9
1\/2+5\/6-7\/12+9\/20-11\/30+13\/42-15\/56 (简便运算)
分析：5\/6=1\/2+1\/3 7\/12=1\/3+1\/4 9\/20=1\/4+1\/5 11\/30=1\/5+1\/6 13\/42=1\/6+1\/7 15\/56=1\/7+1\/8 1\/2+5\/6-7\/12+9\/20-11\/30+13\/42-15\/56 =1\/2+(1\/2+1\/3)-(1\/3+1\/4 )+(1\/4+1\/5 )-(1\/5+1\/6)+(1\/6+1\/7)-(1\/7+...
小学数学计算:1+1\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56,求你了。
两个字仔细
简算1+1\/2+5\/6-7\/12+9\/20-11\/30
解：折开分数，构成新项，中间项彼此相消，仅存首尾项。1＋1／2＋5／6－7／12＋9／20－11／30 = 1+1\/2+(3\/6+2\/6)-(4\/12+3\/12)+(5\/20+4\/20)-(6\/30+5\/30)= 1+1\/2+1\/2+1\/3-1\/3-1\/4+1\/4+1\/5-1\/5-1\/6 = 1+1-1\/6 = 11\/6 补充：从加减号的交错看...
计算:1+1\/2_5\/6+7\/12_9\/20+11\/30_13\/42+15\/56
9\/8 解析：1+1\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56 =1+1\/2-1\/2-1\/3+1\/3+1\/4-1\/4-1\/5+1\/5+1\/6-1\/6-1\/7+1\/7+1\/8 =1+1\/8 =9\/8
