• Replace a variable with its value.

The "constant" command is used to remove a variable (or variables) from the entire set of equations by replacing all occurrences of the variable with its current numeric value.  Once turned into a numeric constant, the variable no longer appears in any equation, and the variable definition is automatically "clear"ed (unless the variable is "lock"ed).

e.g.   f=mg         Enter a basic equation from physics.
       g=9.8        Define "g", the acceleration of gravity.
       constant g   Make "g" a constant, leaving "f=9.8m"

If the need for a constant is not permanent, consider using the "lock" command to create a symbolic constant instead.