The Display command accepts an inert-form structure and displays it in standard math notation.  

Without options inert substructures are displayed in gray. To show the expression so that it looks like an equivalent non-inert expression, use the option inert=false.

Note: Copy & paste of something displayed using option inert=false will paste in the non-inert form of the copied object.

When using the Standard worksheet interface the displayed result will be typeset via the InertForm:-Typeset command.  As of Maple 2017, this is also the default output in a document; even without using the Display command.  Other interfaces will use an alternate approach which may occasionally include extra sets of parentheses.

This function is part of the InertForm package, so it can be used in the short form Display(..) only after executing the command with(InertForm). However, it can always be accessed through the long form of the command by using InertForm[Display](..).

$\mathrm{with}\left(\mathrm{InertForm}\right)\:$

$\mathrm{ex}≔\mathrm{Parse}\left(''(1+2)/6''\right)$

$\mathrm{ex}≔\frac{1+2}{6}$

$\mathrm{lprint}\left(\mathrm{ex}\right)$

(1 %+ 2) %/ 6

$\mathrm{Display}\left(\mathrm{ex}\,'\mathrm{inert}'=\mathrm{false}\right)$

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

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

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