_529_
1) - 1/3
2)1/5
3)1/5
4)-7/7
_530_
1)21-(5-8)=21-3=18;
2)3,7-(4-5,3)=3,7-(-1,3)=5;
3)1/6-(5/12-7/12)=1/6-(-2/12)=1/6-(-1/6)=2/6=1/3
4)-13-(20-32)=-13-(-12)=-1
5)-4,5-(7-9,5)=-4,5-(-2,5)=-2
6)-5/8-(5/8-1)=-5/8-(-3/8)=-2/8=-1/4
7)-18-(9-5)=-18-4=-22
8)-0,25-(3-2,25)=-0,25-0,75=-1
9)-2/9-(1-8/9)=-2/9-1/9=-3/9=-1/3