Răspuns:
ciclul primar are cls : 1,2,3,4
a+a+2+a+4+a+6=412
4a+12=412
4a=412-12
a=400:4
a=100 elevi cls 1
100+2=102 elevi cls 2
100+4=104 elevi cls 3
100+6=106 elevi cls 4
