Dimensional Analysis/Label Factoring

1. Units in scientific calculations are extremely important. They can help you to determine if you correctly solved a problem. They have meaning and should not be discarded, only to be tacked on (or not) to the final answer.
2. You can think of units (cm, m, g, ml, etc.) like algebraic variables (x, y, a, etc.)
3. All of the same operations that you can do with variables you can do with units (sometimes referred to as labels or dimensions). Consider the following:

   a+a =	1 cm + 1 cm =
   2a * 4a =	2 cm * 4 cm =
   15a + 3b =	15 cm + 3 sec =