3/5*(-5/11+5/3) - 5/11*(-3/5+11/5) = -3/5*5/11 + 3/5*5/3 + 5/11*3/5 - 5/11*11/5 = -3/11 + 1 + 3/11 - 1 = 0
11/12*(23/37-12/11) + 23/37*(-11/12+37/23) = 11/12*23/37 - 11/12*12/11 - 23/37*11/12 + 37/23*23/37 = -1 + 1 = 0
4/5*(6/7-5/4) + 6/5*(5/6-4/7) = 4/5*6/7 - 4/5*5/4 + 6/5*5/6 - 6/5*4/7 = 0
11/13*(13/22-3/7) + 3/13*(-13/3+11/7) = 11/13*(13/22-3/7) + 3/13*(11/7-13/3) = 11/13*13/22 - 11/13*3/7 + 3/13*11/7 - 3/13*13/3 = 11/22 - 33/91 + 33/91 - 1 = 0,5 - 1 = - 0,5