Raspunsul:
2.Numerele naturale nenule sunt toate numerele in afara de 0.
1+2+3...+100=S
S=((1+100)*100):2=(101*100):2=10100:2=5050=>Cel putin doua sunt egale
5049-(5050*100):5049-4950=99
1+2+3+...+99+99=5049
Verificare
(1+2+3...99)+99=5049
5049=(((1+99)*99):2)+99=(5500:2)+99=4950+99=5049
