What is the density of an object having a mass of 4.0 g and a volume of 39.0 cubic centimeters?
Density is mass per unit volume.
$${\mathtt{density}} = {\frac{{\mathtt{4}}}{{\mathtt{39}}}} \Rightarrow {\mathtt{density}} = {\mathtt{0.102\: \!564\: \!102\: \!564\: \!102\: \!6}}$$
density ≈ 0.103 g/cc