Question

rezolvați 1+2+3+......+65=

Answer 1

$1 + 2 + 3 + ... + 65 = \frac{65(65 + 1)}{2} = \frac{65 \times 66}{2} = 65 \times 33 = 2145$

Answer 2

1 + 2 + 3 + ........ + 65 = 65 × ( 1 + 65 ) / 2 = 65 × 66 / 2 = 65 × 33 = 2 145

→ am aplicat formula sumei lui Gauss