The NoSimpl module overloads the basic arithmetic and function operators so the given expression, expr, is interpreted to inert form. See InertForm:-Parse for more details about inert form.

Note: Do not try to load this module via the with command.  Because it overrides function calls to make them inert, there will be no way to call other functions and have them evaluate.  If you accidentally do this, use the unwith command to unload the module.

$\mathbf{use}\mathrm{InertForm}:-\mathrm{NoSimpl}\mathbf{in}\frac{1\+2}{6}\mathbf{end\; use}$

$\frac{1+2}{6}$

The InertForm[NoSimpl] command was introduced in Maple 18.

For more information on Maple 18 changes, see Updates in Maple 18.