1) 6,3 : 38 : (−6,3) =

\(6{,}3 : 38 : (-6{,}3)=\dfrac{6{,}3}{38\cdot(-6{,}3)}\)

Сократим \(6{,}3\): \(\dfrac{1}{38\cdot(-1)}=-\dfrac{1}{38}\).

Ответ: \(-\dfrac{1}{38}\).