Question

Suma lui Gaus pentru 1+2+3+...+75

Answer 1

1+2+3+...+75 =
= 75 × (75 + 1) : 2 =
= 75 × 76 : 2 =
= 75 × 38 =
= 2850

Answer 2

$1+2+3+...+75 = \dfrac{75\cdot(75+1)}{2}=\dfrac{75\cdot 76}{2} = 75\cdot 38 = 2850$