Odpowiedź:
a) 4/7 + 3/4 = 16/28+21/28 = 37/28 = 1 i 9/28
b) 3 i 2/7 - 1 i 5/7 = 2 i 9/7 - 1 i 5/7 = 1 i 4/7
c) 5/12 + 9/20 = 25/60 + 27/60 = 52/60
d) 3/5 : 4/7 = 3/5 * 7/4 = 21/20 = 1 i 1/20
