a) 2/3 + 3/7 = 14/21 + 9/21 = 1 i 2/21
5/6 + 8/9 = 15/18 + 16/18 = 1 i 13/18
b) 3 i 3/4 + 1/6 = 3 i 6/12 + 2/12 = 3 i 8/12 = 3 i 2/3
2 i 8/9 + 1 i 7/10 = 2 i 80/90 + 1 i 72/90 = 4 i 62/90
4 i 5/9 + 5 i 1/6 = 4 i 10/18 + 5 i 3/18 = 9 i 13/18
pozdrawiam zjawa :)