Question

s = 1+2+3+4+5+...+79+80

Answer 1

pues la respuesta sale =3174

Answer 2

S = 1+2+3+4+5+6+7+........79+80

S = 1+2+3+4+5+6+7+ ............n = $\frac{n(n+1)}{2}$

n = 80

$S = \frac{n(n+1)}{2} = \frac{80(81)}{2} = \frac{6480}{2} = 3240$