1. 3 1/8-(4 5/16+1 1/4)=25/8-69/16-5/4= 50/16-69/16-20/16= -39/16=-3 7/16
2. -7 3/5-(-4 1/15-5 2/3)= -38/5+61/15+17/5= -114/15+61/15+51/15= -2/15
3. -3 1/2-(5 3/4+2 7/20)=-7/2-23/4-47/20= -70/20-115/20-47/20=-232/20=-11 12/20=-11 3/5
4. -1/3-(-3 7/18-5 8/9)= -1/3+61/18+53/9= -6/18+61/18+106/18= 161/18=8 17/18