$2 \times \dfrac{1}{2} \times 3 \times \dfrac{1}{3} \times 4 \times \dfrac{1}{4} \times 5 \times \dfrac{1}{5}$ $= \dfrac{2}{2} \times \dfrac{3}{3} \times \dfrac{4}{4} \times \dfrac{5}{5}$ $= 1 \times 1 times 1 times 1$ $=1$ Trả lời
$2 \times \dfrac{1}{2} \times 3 \times \dfrac{1}{3} \times 4 \times \dfrac{1}{4} \times 5 \times \dfrac{1}{5}$
$= \dfrac{2}{2} \times \dfrac{3}{3} \times \dfrac{4}{4} \times \dfrac{5}{5}$
$= 1 \times 1 times 1 times 1$
$=1$
2×$\frac{1}{2}$×3×$\frac{1}{3}$×4×$\frac{1}{4}$×5×$\frac{1}{5}$
=1×1×1×1
=1