zad.2
a) 18/60 = 3/10
b) 48/60 = 4/5
c) 75/60 = 1 15/60 = 1 1/4
zad.3
a) 8 4/11 - 5 9/11 = 7 15/11 - 5 9/11 = 2 6/11
b) 8 5/6 + 5 3/8 = 8 20/24 + 5 9/24 = 13 29/24 = 14 4/24 = 14 1/6
c) 7 2/3 - 4 2/5 = 7 10/15 - 4 6/15 = 3 4/15
d) 1 2/7 *4 1/12 = 9/2 * 49/12 = 147/8 = 18 3/8
e) 4 8/15 : 3 2/5 = 68/15 : 17/5 = 68/15 * 5/17 = 4/3 = 1 1/3
