Question 469810
{{{1/2+(2/3)/(3/4)-(4/5)*(5/6)=1/2+(2/3)*(4/3)-(4/cross(5))*(cross(5)/6)=1/2+8/9-2/3=(1*9)/18+(8*2)/18-(2*6)/18=(9+16-12)/18=13/18}}}