1) 5/18 + 4/18=9/18=1/2
2) 25/34 - 8/34=17/34=1/2
3) 3 13/45 + 6 17/45=9 30/45 = 9 6/9= 9 2/3
4) 12 43/56 - 7 22/56=5 21/56=5 3/8
