Odpowiedź:
1/ 28/9-14/9+22/9=
= 14/9+22/9=
= 36/9 =
= 4
2/ 6 - ( 21/5 - 13/5 )=
= 6 - 8/5 =
= 6/1 - 8/5 =
= 30/5 - 8/5 =
= 22/5 =
= 4 i 2/5