Odpowiedź:
4/15 + 3/10 = 8/30 + 9/30 = 17/30
1 i 7/8 + 5 i 3/10 = 1 i 35/40 + 5 i 12/40 = 6 i 47/40 = 7 i 7/40
8/9 - 5/6 = 16/18 - 15/18 = 1/18
5 i 1/4 - 1 i 6/7 = 5 i 7/28 - 1 i 24/28 = 4 i 35/28 - 1 i 24/28 = 3 i 11/28
2 i 8/9 - 2 i 2/5 * 1 i 1/9 = 2 i 8/9 - 12/5 * 10/9 = 2 i 8/9 - 8/3 = 2 i 8/9 - 2 i 2/3 = 2 i 8/9 - 2 i 6/9 = 2/9
(1 i 2/5 + 1 i 3/10) : 1 i 1/5 = (1 i 4/10 + 1 i 3/10) : 1 i 1/5 = 2 i 7/10 : 1 i 1/5 = 27/10 : 6/5 = 27/10 * 5/6 = 27/12 = 2 i 3/12 = 2 i 1/4
