It will be more intuitive to solve this problem with venn diagram combined with analysis.

There are 2 1 person who can play checkers and1person who can play chess, so this1person is included in 2 1 person who can play checkers, so there is no need to repeat the calculation.

Six of the 16 people who can play gobang are also included in the1people who can play checkers, so there is no need to repeat the calculation. Other 10 people can't play checkers or chess (because if they can play chess, they can all play checkers under the known conditions, which will lead to conflicts).

So 2 1 person can play checkers and chess.