1/x(x+1)+1/(x+1)(x+2)+1/(x+2)(x+3)-1/x=1/2010, 1/x(x+1) + 1/(x+1)(x+2) + 1/(x+2)(x+3) - 1/x = 1/2010, 1/x(x + 1) + 1/(x + 1)(x + 2) + 1/(x + 2)(x + 3) - 1/x = 1/2010