1) =4 (3-10)/16= 3 (19-10)/16=3 9/16
2) = 3 (28-54)/63=2 (63+28-54)/63=2 37/63
3) = 2 (33-38)/72=1 (72+33-38)/72=1 37/72
4) = 4 (2-9)/12=3 (12+2-9)/12=3 5/12
