Răspunsuri

  • Utilizator Brainly
2014-09-16T14:37:25+03:00
2014-09-16T15:55:02+03:00
Regula: 1+2+3+...+n=n(n+1)/2
In cazul nostru: 1+2+3+...+20= 20(20+1)/2
20 x 21 : 2...