Use Your Knowledge of English: 

Find the mass in grains of a 325 milligram aspirin tablet.
(Given: 1.00 g = 15.4 grains)

_???__grains = 325 milligram tablet

1. From the Problem write down all the Equivalent Relationships given or Unit Factors.    For example:
  • 1.00 g = 15.4 grains
2. Beware of our Tricks!
  • We disguise numbers by making them words.
  • We leave out obvious equivalent relationships, or             relationships we think you should know.

  • We stick extra information in the form of numbers and equivalent relationship you will not need to solve the problem

    The only unit factor left out is the 1000 mg = 1 g equivalence.

    Two Step Dimensional Analysis Map

    3. Formulate a road map which connects the given unit to the answer unit by equivalent relationships:

    Since grains are Apothecary system of mass and milligrams are metric mass, this is a simple Mass to Mass problem.

    The bridge from Metric to Apothecary is the Unit Factor given:
    15.4 grain = 1 g.

    The Solution:

      ??? grain = 325 mg X 1 g X 15.4 grain = 5.01 grain  

    1 1 1000 mg 1 g 1