Question

1+2+3+4.......................................................................................+231=

Answer 1

(231*232):2 = 231*116=26796

Answer 2

$\displaystyle 1+2+3+4+...+231= \frac{231(231+1)}{2} = \frac{231 \times 232}{2} = \frac{53592}{2} =26796$