4. Fill the numbers into the 6 vertices of the hexagon , and let represent the sums of the numbers at the 3 adjacent vertices respectively.
(1) Try to give a way to fill the numbers so that are all greater than or equal to 9;
(2) Can you find a way to fill the numbers so that are all greater than or equal to 10? If yes, provide a specific way to fill the numbers; if not, explain the reason.
Problem 304
Official solution
4. (1) There are many ways to fill, omitted. (2) They can all be greater than or equal to 10, see Figure 7.