If one is calculating the number of teaspoons in 25 milligrams of lead, for example, the density is 11.34 grams per cubic centimeter. There are 1,000 milligrams in a gram and 4.93 cubic centimeters in a teaspoon, so the density is 2,300.2 milligrams per teaspoon. Dividing the 25 milligrams of lead by the 2,300.2 milligrams per teaspoon provides a result of roughly 0.1 teaspoon.