A. 3-(2/14+5/14)=
3-7/14=
3-1/2=
6/2-1/2=
5/2=
2×1/2
3-(12/14-9/14)=
3-3/14=
42/13-3/14=
39/14
2×11/14
B. 3/6-1/6=2/6 a 2 a zi
2/6+2/6=5/6 in cele 2 zile
6/6 -5/6=1/6 mai are
C. 1/15+2/15=3/15 a 2 a zi
1/15+3/15=4/15 a 3 a zi
1/15+3/15+4/15=8/15 in cele 3 zile
15/15-8/15=7/15 a 4 a zi