Theory:

3. Impress:
Impress is a basic presentation application that provides all the common multimedia presentation tools, such as special effects, animation, editing modes, and drawing tools.
All these features make the presentation work easier. They add style to the presentation and give life to it by making slideshows and animation effects.
 
libre impress.jpg
LibreOffice Impress
  
4. Draw:
Draw is a vector graphics drawing tool that can produce any simple diagram, flowchart, and even \(3D\) artwork. It mainly helps in making technical drawings, posters, documents, photo albums, etc.
 
Draw.png
LibreOffice Draw
  
5. Base:
Base is a database software tool that makes the database work within a simple interface. Base provides users to create and edit forms, reports, queries, tables, views, and relations.
So, it is easier to manage a relational database like the other popular database applications like Microsoft. It is an easy-to-understand and simple-to-use system to store data.
 
LibreOffice-Base--Version-6.0.6.2--Ubuntu-16.04.png
LibreOffice Base
  
6. Math:
Math is the formula or equation editor in LibreOffice.
Several math symbols and characters used in equations are not available in standard font sets. But with the help of this formula editor, one can create complex equations with various symbols or characters.
 
math.png
LibreOffice Math
Reference:
https://i.ytimg.com/vi/xB9A_HrS_SU/maxresdefault.jpg
https://design.blog.documentfoundation.org/wp-content/uploads/sites/2/2016/07/20160731_DrawUI.png
https://upload.wikimedia.org/wikipedia/commons/0/01/LibreOffice-Base--Version-6.0.6.2--Ubuntu-16.04.png
https://elearn.ellak.gr/pluginfile.php/3987/mod_page/content/12/math-main-window.png