31*1=31;
15,5*2=31;
10,(3)*3=31;
7,75*4=31;
6,2*5=31;
5,1(6)*6=31;
4,42...*7=31;
3,875*8=31;
3,(4)*9=31;
3,1*10=31;
2,(81)*11=31;
2,58(3)*12=31;
2,38...*13=31;
si altele
cifrele din parantezele()insemna ca se repeta pina la infinit
...insemna ca urmeaza si alte cifre
