下列问题如何解答

因为：2/(1×2×3)=1/(1×2)－1/(2×3)
2/(2×3×4)=1/(2×3)－1/(3×4)
2/(3×4×5)=1/(3×4)－1/(4×5)
……
2/(8×9×10)=1/(8×9)－1/(9×10)
所以：2/(1×2×3)+2/(2×3×4)+2/(3×4×5)+……+2/(8×9×10)
=1/(1×2)－1/(2×3)＋1/(2×3)－1/(3×4)＋1/(3×4)－1/(4×5)＋……＋1/(8×9)－1/(9×10)
=1/(1×2)－1/(9×10)
=1/2－1/90
=22/45

2/(1*2*3)=1/(1*2)-1/(2*3)
2/(2*3*4)=1/(2*3)-1/(3*4)
……
2/（1*2*3）+2/（2*3*4）+2/（3*4*5）+...+2/(8*9*10)
=1/2-1/90
=22/45