1. 8,3-10=-1,7

2. -2 1/2-(-3)=-2 1/2+3=-2 1/2+2 2/2=1/2

3. 9 1/5-(-13 3/5)=46/5+68/5=114/5=22 4/5

4. -4,75-3 1/4=-4,75-3,25=-8

5. -13,94-(-20)=-13,94+20=6,06