5)9-pachete(a cate 9 carti in fiecare)
7-pachete vandute
?carti ramase
1mod)9*9=81 carti
7*9=63carti vandute
81-63=18 carti ramase
2mod)9*9=81carti
7*9=63carti vandute
9-7=2pachete ramase
2*9=18carti ramase
ex6)a+b+c=?
a=c*2
b=a+27
c=61-59
c=2
a=2*2=4
b=4+27=31
4+31+2=37
a+b+c=37