(11/30 - 17/36) : 19/45 = (-1/4)
1) 11/30 - 17/36 = 66/180 - 85/180 = (-19/180)
2) (-19/180) : 19/45 = (-19/180) * 45/19 = (-45/180) = (-1/4)
(17/16 - 1/32) : 11/24 = 2 1/4
1) 17/16 - 1/32 = 34/32 - 1/32 = 33/32
2) 33/32 : 11/24 = 33/32 * 24/11 = (3*3)/(4*1) = 9/4 = 2 1/4