### 4.3.1 Entering expressions in the editor

The expression

can be entered on the command line with

(x+2)/(x^2-4)

You also can use the expression editor to
enter it visually, as x+2 on top of x^{2} − 4. To do this, you can
start the expression editor with the Alt+E keystroke (or the
Expression ▸ New Expression menu
command). There will be a small M on the right side of the
expression line, which is a menu with some commands you can use on the
expressions. There will also be a 0 selected on the
expression line and an on-screen keyboard at the bottom. If you type
x + 2, it will overwrite the 0. To make this the
top of the fraction, you can select it with the mouse (you can also
make selections with the keyboard, as will be discussed later) and
then type /. This will leave the x + 2 on the top
and the cursor on the bottom. To enter x^{2} − 4 on the bottom, begin
by typing x. Selecting this x and typing
^2 will put on the superscript. Finally, selecting the
x^{2} and typing - 4 will finish the
bottom. If you then hit Enter, the expression will be
evaluated and will appear on the output line.