Units > Unit Placeholders
  
Unit Placeholders
Unit placeholders only appear if they contain units or when you activate their region. Although the primary role of a unit placeholder is to display units, they can be used for scaling as they accept any expression such as π or a predefined variable name. Unit placeholders are located in the following locations:
Math regions—When you evaluate an expression, a unit placeholder appears to the right of the result.
Plots—Each axis expression in a plot has a unit placeholder to its right associated with the trace displayed.
Tables—The elements in the second row of tables are unit placeholders associated with the column data sets. Since the units in these placeholders are used for definition and not for displaying the units after evaluation, when you delete the units, no unit balancing occurs.