The maximum degree can be at most 2 * number of edges / number of vertices. Here, it is 2 * 12 / 8 = 3.

In a complete graph with 4 vertices, each vertex is connected to 3 others, so the degree of each vertex is 3.

The average degree of a graph is given by 2 * number of edges / number of vertices. Here, it is 2 * 12 / 8 = 3.

In a bipartite graph, the maximum number of edges is the product of the sizes of the two sets. Here, it is 4 * 6 = 24.

The total number of edges in a directed graph is the sum of the out-degrees. Here, it is 6 * 3 = 18.

The maximum number of edges in a simple graph with n vertices is given by n(n-1)/2. For n=5, it is 5(5-1)/2 = 10.

The total number of edges is half the sum of the degrees. Here, (4*6)/2 = 12.

A tree with n vertices has exactly n-1 edges. For 7 vertices, it requires 7-1 = 6 edges.

The total number of edges is half the sum of the degrees. Here, (3+3+2+2+2)/2 = 6.

A complete graph with n vertices has n(n-1)/2 edges.