You can't directly convert milligrams (mg) to milliliters (ml) because they measure different things:

* Milligrams (mg) measure mass or weight.

* Milliliters (ml) measure volume.

To convert between mass and volume, you need to know the density of the substance. Density is the mass per unit volume.

Here's an example:

* Water has a density of approximately 1 gram per milliliter (g/ml).

* So, 80 milligrams of water would equal 0.08 milliliters (because 80 mg is equal to 0.08 grams).

To convert milligrams to milliliters, you need to know the density of the substance you are working with.