217/15 - 72/27 - 1/5 = 217/15 - 8/3 - 1/5 = 217/15 - 40/15 - 3/15 = 11,6
(53/9 : 53/36 +5/4) * 5/21 = (53/9 * 36/53 + 5/21) *5/21 = (4 + 5/4) * 5/21 = 21/4 * 5/21 = 5/4 = 1,25
-6 : (-0,6) - 5,6 = 10 - 5,6 = 4,4
(-11/8 - 29/12) : 65/12 = (-33/24 - 58/24) : 65/12 = -91/24 * 12/65 = --91/2 * 1/65 = -91/130 = -7/10