Oblicz :
1-2/5=
2-5/6=
3 - 1 5/6=
4 - 1 7/10=
9- 3 11/15=
9 - 4 2/7=
5 - 1 6/13
10 - 3 5/18=
2/5 - 1/4=
4/7 - 1/6=
1/2 - 3/9=
3/4 - 2/3=
7/8 - 1/3=
1/8 + 1/5 =
3/7 + 1/4=
1/3 + 1/5=.