计算题!能简算的要简算哦~

题目

计算题!能简算的要简算哦~
(1) 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6
(2)
2/2x4+2/4x6+2/6x8+.+2/10x12

答案

(1/1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)=1-1/6=5/6
(2)
化简跟(1) 一样