Express as a difference of logarithms. Assume $\mathrm{z}$ is a positive real number. \[ \log \frac{10}{z} \] \[ \log \frac{10}{z}=\square \] (Type an exact answer in simplified form.)

Step 1 ：Express the given expression as a difference of logarithms. Assume z is a positive real number: \(\log \frac{10}{z}\).

Step 2 ：According to the properties of logarithms, the logarithm of a quotient is equal to the difference of the logarithms of the numerator and the denominator.

Step 3 ：Therefore, we can express the given expression as the difference of the logarithm of 10 and the logarithm of z: \(\log 10 - \log z\).

Step 4 ：Final Answer: \(\boxed{\log 10 - \log z}\)