Answer:
A Venn diagram uses circles to represent relationships between groups (sets in mathematics). The circles that overlap tell us that the groups share a trait. The circles that do not overlap tells us that the groups represented do not share any traits. The greater the overlap of circle areas, the more similar the represented groups are.
To put it simply, Venn Diagrams are important in that they visually tell us whether distinct groups share any similarly, if yes, to what extent. Therefore, the Venn diagrams are important in understanding relationships between mathematical sets.