3/2-5/6+7/12-9/20+11/30-13/42+15/56等于多少

用简便方法求解:3\/2-5\/6+7\/12-9\/20+11\/20-13\/42+15\/56=?
3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56 =(1\/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 根据题目规律，11\/20应该是11\/30，你看下原题是否如此，如我上面解答对你有启发，请记得采纳。

3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56
(1\/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)=9\/8 即3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56=1又1\/8

一道数学难题
3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56 你会发现分子上是3,5,7,9,11,13,15,分母是2,6,12,20,30,42,56 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+1\/8=9\/8 ...

3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56求解答
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 所以 3\/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 =7\/8...

3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56 简便运算? = = =
裂项法：3\/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 =1又1\/8

3\/2-5\/6+7\/12-9\/20+11\/30-42\/13+15\/56求解谢谢,急!!!
3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56 =(1+2)\/(1×2)-(2+3)\/(2×3)+(3+4)\/(3×4)-(4+5)\/(4×5)+(5+6)\/(5×6)-(6+7)\/(6×7)+(7+8)\/(7×8)=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[3\/2]-[5\/6]+[7\/12]-[9\/20]+[11\/30]-[13\/42]+[15\/56]?
,7,①[3\/2]-[5\/6]+[7\/12]-[9\/20]+[11\/30]-[13\/42]+[15\/56]②[ 2 4 5 +（ 3 2 3 -2.75）÷ 1 5 6 ]÷ 3 1 5 ③ 5. • 3 • 6 -（7.2-1.28×2.5）÷11 ④[1×2×3+2×4×6+7×14×21\/1×3×5+2×6×10+7×21×35...

3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56 怎样计算?
回答：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+1\/8=9\/8

3\/2-5\/6+7\/12-9\/20+11\/30-13\/42+15\/56的简算法?
3／2一5／6十7／12一9／20十11／30一13／42＋15／56 ＝（30／20一9／20）＋（7／12一10／12）＋（45／168一52／168）＝21／20-1／4一1／24 ＝21／20一5／20一1／24 ＝3／10一1／24 ＝36／120-5／120 ＝31／120

3\/2一5\/6十7\/12一9\/20十11\/30一13\/42十15\/56怎么算
3\/2一5\/6十7\/12一9\/20十11\/30一13\/42十15\/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 （去括号）=9\/8