Odpowiedź:
3/7 + 1/7 = 4/7
5/8 * 8 = 40/8 = 5
5/9 + 7/18 = 10/18 + 7/18 = 17/18
13/15 * 5/8 = 13/24
14/17 - 5/17 = 9/17
12/19 : 3 = 12/19 * 1/3 = 12/57
2/3 - 1/4 = 8/12 - 3/12 = 5/12
5/8 : 7/8 = 5/8 * 8/7 = 5/7
7 i 5/12 - 2 i 11/15 = 7 i 25/60 - 2 i 44/ 60 = 6 i 85/60 - 2 i 44/60 = 4 i 41/60