There is a useful way to express a set with a picture.
Picture or diagram of this kind is called "Venn Diagram". The name is in accordance with the name of the inventor, namely John Venn, a British mathematician who lived during the years 1834 to 1923.
Rules of the image sets with Venn diagrams:
The Universe set is depicted by rectangles. All elements of the universe is drawn as the dots.
Subset of the universe talks depicted by a closed curve that surrounds the dots belonging to its members.
For example:
U = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10} with a subset K = {3, 7, 5} and L = {2, 4} , his Venn diagram :
Fig. 2. 
If a member of the set was too much to be drawn as a dot, then the diagram of its members were not described, simply described set form only, or square and a closed curve with the name alone.
For example :
U = {Senior High Schools in Indonesia}, L = { Senior High Schools in Jakarta and }
K = { Senior High School in North Jakarta }, his Venn diagram:
Fig. 3.
The use of shading or color in the Venn diagram will generate a clearer diagram.
