### 5. How to Write Math Notes

#### Create Notes

For mouse-operated devices, use the mouse to select a text. For touch-capable devices, use long press (tap and hold for about 1 second) to select a text. A menu will appear at the bottom for "highlight", "Notes" and "Links". Click on "Note" to bring up an edit box.

#### Limitation

In the current version of the Viewer, you cannot select mathematical expressions.

#### View Notes

Notes are indicated by the background color nnnnnnnnnn. Clicking on a note will bring up a view box which displays the rendered math expression, whereas the edit box displays the original code.

#### Edit Notes

Simply click on the symbol E at the bottom left of the view box. This will bring up the edit box. Clicking on "View" in the edit box will also show the view box, which allows you to preview the rendered expression before you save the note.

#### Delimiters

To indicate whether the typed characters represent LaTeX, AsciiMath or regular text, your code should begin and end with some delimiters.

##### LaTeX:

: Begin or end of an equation.

\]: End displayed equation .

\[: Begin displayed equation.

\): End in-line math expression.

\(: Begin in-line math expression.

Please note that a single \$ is not supported because it is commonly used in a text.

##### AsciiMath

Use backquote (`) for the beginning and ending of an expression which may mix with text in a paragraph. This standard delimiter is located at the top left of a physical keyboard [same as tilde (~)]. However, it is missing in some mobile devices. Therefore, the Viewer also supports a custom delimiter: two consecutive tildes (~~) on both sides of an expression.