最佳答案
回答者：网友
解：
原式
=1/4+1/28+1/70+1/130+1/208+1/24-1/28
=1/(1×4)+1/(4×7)+1/(7×10)+1/(10×13)+1/(13×16)+1/24-1/28
=1/3×(1-1/4+1/4-1/7+1/7-1/10+1/10-1/13+1/13-1/16)+1/24-1/28
=1/3×(1-1/16)+1/24-1/28
=1/3×15/16+1/24-1/28
=5/16+1/24-1/28
=15/48+2/48-1/28
=17/48-1/28
=119/336-12/336
=107/336
