Question

without counting the we can answer it 1+3+5+7+9+11+13+15+17+19+21+23+25+27+29+31 = ?

Answer 1

$\frac{16}{2} \times (2 \times 1 + (16 - 1) \times 2) = 8 \times (2 + 30) = 32 \times 8 = 256$