Question

Cum se calculeaza :1+3+5+7+...+99 . Dau coroana. :-)

Answer 1

1 = 2 x 0 + 1
3 = 2 x 1 + 1
5 = 2 x 2 + 1
.......................
99 = 2 x 49 + 1

S = (2 x 0 + 1) + (2 x 1 + 1) + (2 x 2 + 1) + .... + (2 x 49 + 1)
S = 2(1 + 2 + ...+49) + 1 x 50
S = 2 x 49 x 50 : 2 + 50
S = 49 x 50 + 50
S = 2450 +50
S = 2500

Answer 2

1+3+5+7+.........+99=
Aflam cate nr sunt=50
Aflam suma=1+99=100
50×100:2=2500
50×50=2500
Sper ca te-an ajutat!!!!!!!!