5 ⋅ 5² ⋅ 5⁴ / (5²)³

$$ \frac{5 \cdot 5^2 \cdot 5^4}{(5^2)^3} = \frac{5^{1+2+4}}{5^{2 \cdot 3}} = \frac{5^7}{5^6} = 5^{7-6} = 5^1 = 5 $$