[tex]1 + 2 + 3 + ... + 60 = \\ 60 \times 61 \div 2 = \\ 3660 \div 2 = \\ = 1830[/tex]
Formula lui Gauss:
[tex]\it 1+2+3+\ ...\ +n=\dfrac{n(n+1)}{2}\\ \\ \\ 1+2+3+\ ...\ +60=\dfrac{60\cdot61}{2}=30\cdot61=1830[/tex]
