1-5/6+7/12-9/20+11/30-13/42+15/56-17/72+19/90=?简便运算
1-5/6+7/12-9/20+11/30-13/42+15/56-17/72+19/90=?巧算
=1/6+7/12-9/20+11/30-13/42+15/56-17/72+19/90
=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+1/9+1/10
=1/2+1/10
=(5+1)/10
=6/10
=3/5追问
不太懂，能清楚点嘛？草稿算好拍照我看看，谢谢谢谢
追答1-5/6=1/6=1/2-1/3
7/12=3/12+4/12=1/3+1/4
9/20=4/20+5/20=1/4+1/5
11/30=5/30+6/30=1/5+1/6
13/42=6/42+7/42=1/6+1/7
15/56=7/56+8/56=1/7+1/8
17/72=8/72+9/72=1/8+1/9
19/90=9/90+10/90=1/9+1/10
这样能看明白了吗？
1-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72+19\/90 简便计算
1 - 5\/6 + 7\/12 - 9\/20 + 11\/30 - 13\/42 + 15\/56 - 17\/72 + 19\/90= 1 - (3+2)\/6 + (4+3)\/12 - (5+4)\/20 + (6+5)\/30 - (7+6)\/42 + (8+7)\/56 - (9+8)\/72 + (10+9)\/90= 1 - 1\/2 - 1\/3 + 1\/3 + 1\/4 - 1\/4 - 1\/5 + 1\/5 + ...
1-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72+19\/90要简便.
1-5／6+7／12-9\/20+11\/30-13\/42+15\/56-17\/72+19\/90 =1\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72+19\/90 =3\/4-9\/20+11\/30-13\/42+15\/56-17\/72+19\/90 =6\/20+11\/30-13\/42+15\/56-17\/72+19\/90 =20\/30-13\/42+15\/56-17\/72+19\/90 =15\/42+15\/56-17\/72+19\/9...
1-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-14\/72+90\/19等于多少
题中的“14\/72”错啦，应该是“17\/72”；还有“90\/19”的分子分母写反啦，应该是“19\/90”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 17\/72=1\/8＋1\/9 19\/90=1\/9＋1\/10 1-5\/6＋7\/12-9\/20＋11\/30-1...
简便计算 1-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72
1-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72 =1-(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\/9 =1\/2-1\/9 =9\/18-2\/18 =7\/18
1-5\/6+7\/12-9\/20+11\/30-13\/42,加15\/56-17\/72,加19\/90。
解：依题意得算式，1-6分之5+12分之7-20分之9+30分之11-42分之13+56分之15-72分之17+90分之19 =1-（2分之1+3分之1）+（3分之1+4分之1）-（4分之1+5分之1）+（5分之1+6分之1）-（6分之1+7分之1）+（7分之1+8分之1）-（8分之1+9分之1）+（9分之1+10分之1...
请教各位。1-6\/5+12\/7-20\/9+30\/11-42\/13+56\/15-72\/17 如何简便...
1-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72 =1-1\/2-1\/3+1\/3+1\/4-……-1\/8-1\/9 =1-1\/2-1\/9 =7\/18
1-6\/5+12\/7-20\/9+30\/11-42\/13+56\/15-72\/17 如何简便计算.
1-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72 =1-1\/2-1\/3+1\/3+1\/4-……-1\/8-1\/9 =1-1\/2-1\/9 =7\/18
1-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72登月多少,用简便方法
2012-06-26 小学数学题解答1-5\/6+7\/12-9\/20+11\/30-1... 6 2005-09-06 1-5\/6+7\/12-9\/20+11\/30-13\/42+15... 46 2015-02-08 1-5\/6+7\/12-9\/20+11\/30-13\/42+15... 4 2011-09-14 1-5\/6+7\/12-9\/20+11\/30-13\/42+15... 60 2016-12-27 1-5\/6+7\/12-9\/20+11...
分数简便计算 1-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72
1-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72 =1-1\/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\/2-1\/9 =7\/18
1-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56这道题用简便方法杂做?
这种多项分数加减的题目，多数是用所谓的列项法来做。其中5\/6=1\/2+1\/3依次下去。所以原式=1-（1\/2+1\/3）+（1\/3+1\/4）-（1\/4+1\/5）+...=1-1\/2-1\/3+1\/3...-1\/7+1\/7+1\/8 =1\/2+1\/8=5\/8
