Răspuns :
4 /7 - 2 / 7 = 2 / 7
5 / 7 - 2 / 7 =3 / 7
7 / 2 - 2 / 2 = 5 / 2
l............................
5 / 7 - 2 / 7 =3 / 7
7 / 2 - 2 / 2 = 5 / 2
l............................