Odpowiedź:
3 i 1/3 - 1 i 4/7 = 3 i 7/21 - 1 i 12/21 = 2 i 28/21 - 1 i 12/21 = 1 i 16/21
7 i 1/9 - 4 i 1/3 = 7 i 1/9 - 4 i 3/9 = 6 i 10/9 - 4 i 3/9 = 2 i 7/9
5 i 3/5 - 2 i 1/8 = 5 i 24/40 - 2 i 5/40 = 3 i 19/40
4 i 3/7 - 1 i 3/4 = 4 i 12/28 - 1 i 21/28 = 3 i 40/28 - 1 i 21/28 = 2 i 19/28
