3 numere pare consecutive
2a+2
2a+4
2a+6
2a+2+2a+4+2a+6=6a+12
Nr. impare consecutive ce se afla intre ele
2a+3
2a+5
2a+3+2a+5=4a+8
6a+12-(4a+8)=12
6a+12-4a-8=12
2a=8
a=4
Nr. sunt
2x4+2=10
2x4+4=12
2x4+6=14
Nr. Impare
2x4+3=11
2x4+5=13
Verificare
10+12+14=36
11+13=24
36-24=12