Hot keys or quick keys are the keyboard combinations that can be used to easily perform a desired action. For example, if you want to quickly save your document, instead of going through the menu bar, or even the toolbar, you can just press <Ctrl> and <s> at the same time. This saves time, and makes performing actions even easier.
|Zoom In||Ctrl+Num+ (the + symbol)|
|Zoom Out||Ctrl+Num+ (the - symbol)|