1/1*2=1-1/1*2.2/1*2*3=1/1*2-1/1*2*3.3/1*2*3*4=1/1*2*3-1/1*2*3*4.......9/1*2*3*...*10=1/1*2*3*...*9-1/1*2*3*...*10相加得，原式=1-1/1*2*3*4*5*6*7*8*9*10=3628799/3628800.
