probabilitatea=cazuri favorabile/cazuri total posibile
1)nr naturale de 2 cire de la 1 la 100 sunt : 10...99 adica 99-10+1=90 de numere
probabilitatea= 90/100=9/10
2)x²<900
patratele perfecte pana la 100 sunt 1,4,9,16,25,36,49,64,81,100,in total 10 nr
probabilitatea= 10/100=1/10
3)M6{6,12,24,30,36,42,48,54,60,66,72,78,84,90,96 in total 15 nr
probabilitatea= 15/100=3/20