1/1*2*3 + 1/2*3*4 +1/3*4*5 +...+1/8*9*10
=(1/2)[1/1*2 - 1/2*3 + 1/2*3 - 1/3*4 + 1/3*4 - 1/4*5 +...+1/7*8 - 1/8*9 + 1/8*9 - 1/9*10]
=(1/2)(1/1*2 - 1/9*10)
=11/45