If $0.04\times X=0.000016$, then $X=$ ?

Given the equation:
$$0.04\times X=0.000016$$

Isolating $X$:

$$X=\frac{0.000016}{0.04}$$

Converting decimals to scientific notation or simple fractions:

$$X=\frac{16\times 10^{-6}}{4\times 10^{-2}}$$

$$X=\left(\frac{16}{4}\right)\times 10^{-6-(-2)}$$

$$X=4\times 10^{-4}$$

$$X=0.0004$$