Oblicz:
a)-1,7+0,9=
18+(-20,7)=
-2,7+(-3,6)=
-3,4-(-1,5)=

b) 1/4 - 1/5=
-7/12 -3/8=
-3 i 1/5- 2 i 1/2=
1 i 1/6-(-2 i 1/12)=

c) 3,7-4 i 2/5=
-7/8+(0,7)=
1,4-(1 i 3/4)=
-2 i 1/6 -(-1,6)=