a/b * c/d = ac/bd 3/4 * 4/5 = 12/20 = 3/5 12/18 * 1/2 = 12/36 = 1/3
2 3/4 = 11/4 1 3/8 = 11/8 4 3/16 = 67/16 a/b * c/d = ac/bd 2 3/8 * 1 3/4 = 19/8 * 7/4 = 133/32 = 4 5/32 1 1/16 * 2 = 17/16 * 2/1 = 34/16 = 2 1/8