3/2-5/6+7/12-9/20+11/30-13/42+15/56-17/72 这是2009年11月6日总第1037期,小数报六年级版的一条题目,哪位大侠会解的帮下忙。第一个3/2实际上是一又二分之一。
3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72
3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72 原式=(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 3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72= 3\/2-5\/6+7\/12-9\/...
3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72=
3\/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)-(1\/8+1\/9)=1-1\/9 =8\/9
3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72+19\/90。。。求解~急_百度...
3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56-17\/72+19\/90 =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\/9+1\/10 =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\/...
1-3\/2+5\/6-7\/12+9\/20-11\/30+13\/42-15\/56+17\/72-19\/90+21\/110=?_百度...
1-3\/2+5\/6-7\/12+9\/20-11\/30+13\/42-15\/56+17\/72-19\/90+21\/110=?掌握规律是先减号后加号,分子是1、3、5、7、9、11、13、15、17、19、21等奇数,分母数为前一个数的分母加上两个数分子即奇数间的偶数,问题的虚线处应填为...
...20分之9+30分之11-42分之13+15分之56-72分之17 简便运算
15分之56是56分之15吧 2分之3-6分之5+12分之7-20分之9+30分之11-42分之13+65分之15-72分之17 =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
7\/12-9\/20+11\/30-13\/42+15\/56-17\/72简便方法计算?
计算 7\/12-9\/20+11\/30-13\/42+15\/56-17\/72 =(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\/3-1\/9 =3\/9-1\/9 =2\/9
用简便计算 7\/12+9\/20+11\/30-13\/42+15\/56-17\/72
7\/12-9\/20+11\/30-13\/42+15\/56-17\/72 =(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\/3-1\/9 =2\/9 是这样的,因为7\/12=1\/3+1\/4,9\/12=1\/4+1\/5,后面的每一项都可以这样替换 ...
计算:7╱12-9╱20+11╱30-13╱42+15╱56-17╱72。
7╱12-9╱20+11╱30-13╱42+15╱56-17╱72 =(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\/3+1\/4-1\/4-1\/5+1\/5+1\/6-1\/6-1\/7+1\/7+1\/8-1\/8-1\/9 =1\/3-1\/9 =2\/9 ...
7\/12减9\/20加11\/30减13\/42在15\/56减17\/72
7\/12减9\/20加11\/30减13\/42在15\/56减17\/72 =(3+4)\/(3x4)-(4+5)\/(4x5)+(5+6)\/(5x6)-(6+7)\/(6x7)+(7+8)\/(7x8)-(8+9)\/(8x9)=(1\/3+1\/4)-(1\/4+1\/5)+(1\/5+1\/6)-(\/16+1\/7)+(1\/7+1\/8)-(1\/8+1\/9)=1\/3-1\/9 =2\/9 ...
7\/12-9\/20+11\/30-13\/42+15\/56-17\/72简便方法计算
上面的算错了7\/12-9\/20+11\/30-13\/42+15\/56-17\/72=(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\/3+1\/4-1\/4-1\/5+1\/5+1\/6-1\/6-1\/7+1\/7+1\/8-1\/8-1\/9=1\/3-1\/9=2\/9 ...