Question

Cat fac 2+4+6+8+10+12+...+98 ? Dau coroana . :-)

Answer 1

2+4+6+8+10+12+...+98=2(1+2+3+4+5+6+...+49)=2·49(49+1)/2=49·50=2450

Answer 2

este suma lui Gauss
nr×(nr+1):2
2+4+6+8+....+98=
=2×(1+2+3+4+...+49)
=2×49×(49+1):2
=49×50
=2450