15. In the 6 circles below, fill in $0,1,2,3,4,5$ with each number used only once, so that the sum of the three numbers on each side is equal.
【Key Point】Number Array Diagram【Difficulty】Adjacent
【Answer】
【Analysis】Let the 3 vertices be $a, b, c, 0+1+2+3+4+5+a+b+c=15+a+b+c$ is the sum of the 3 edges, $a+b+c$ is a multiple of 3. When $a+b+c=0+1+2=3$, the sum of each edge is $(15+3) \div 3=6$. By rotating the two numbers above, 4 more results can be obtained.