4. Write three numerical expressions that are equivalent to \( (0.0004) \cdot(0.005 \)

When you multiply \(0.0004\) by \(0.005\), you can express this product in various ways. For instance, \( (4 \times 10^{-4}) \cdot (5 \times 10^{-3}) \) simplifies to \( 20 \times 10^{-7} \), or \( 2 \times 10^{-6} \). Another equivalent expression is \( \frac{4}{10000} \cdot \frac{5}{1000} \), which also gives you the same result when computed. Lastly, you could represent it as \( \frac{20}{10000000} \) to maintain a fraction format, showcasing yet another side of mathematical equivalence!