Răspunsuri

Cel mai inteligent răspuns!
2014-09-25T20:21:54+03:00
(1+2)+(2+3)+(3+4)+...+(99+100)=(1+2+3+...+99)+(2+3+4+...+100)=99×50+(50×101)-1=4950+5050-1=4950+5049=9999
1 5 1