y=2c1+1;
y=3c2+1;
y=4c3+1;
y=5c4+1;
y=6c5+1;
⇒2c1=3c2=4c3=5c4=6c5;
⇒y=7c6;
⇒2c1=3c2=4c3=5c4=6c5=7c6;
⇒2 ,3 ,5 ,7⇒numere prime;
⇒4=2²⇒descompunere in factori primi;
⇒6=2·3;
⇒c.m.m.m.c=2²·3·5·7=4·3·5·7=12·5·7=60·7=420[de piese ambalate-numar minin];