1) 5/9 - 5/15 : 14/30 = 5/9 - 1/3 : 14/30 = 5/9 - 1/3 * 30/14 = 5/9 - 10/14 = 5/9 - 5/7 = (35 - 45) / 63 = -10/63.
2) 5/18 - 11/27 : (-2 5/16) = 5/18 - 11/27 : (-37/16) = 5/18 - 11/27 * (-16/37) = 5/18 + 176/999 = (5 * 55.5 + 176) / 999 = (277.5 + 176) / 999 = 453.5 / 999.