The correct formula for calculating density is:

$\text{Density} = \frac{\text{Mass}}{\text{Volume}}$

So, the correct answer is:

Volume/mass.

Would you like more details or have any further questions?

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Here are 5 related questions to explore:

1. How does density change with temperature for most substances?
2. What is the relationship between density and buoyancy?
3. How do you convert between different units of density, such as g/cm³ to kg/m³?
4. How can you calculate the mass of an object if you know its density and volume?
5. What is the concept of relative density (specific gravity)?

Tip: Remember that density is often affected by temperature and pressure, especially for gases.