Răspuns:
Explicație pas cu pas:
28:2= (20+8):2=20:2+8:2=10+4=14
66:6= (60+6):6=60:6+6:6=10+1=11
24:2=(20+4):2= 20:2 +4:2=10+2=12
60:2= (60+0):2= 60:2+0:2= 30+0=30
39:3= (30+9):3= 30:3+9:3= 10+3= 13
33:3=(30+3):3 =30:3+3:3= 10+1=11
65:5=(60+5):5= 60:5+5:5= 12+1=13
dar mie imi pare mai usor la ultima
(50+15):5=50:5+15:5=10+3=13