Răspuns:
Explicație pas cu pas:
1/6+5/4=4/24+11/24=15/24
13/21+12/14=26/42+39/42=65/42
4/15+1/20=16+60+3/60=19/60
11/14+3/35=55/70+6/70=61/70
1/8+7/12=3/24+14/24=17/24
5/33+1/22=10/66+3/66=13/66