If BACKGAMMON is reverse of CONNECT4
OTHELLO is BACKGAMMON and MONOPOLY together
TRIVIAL PURSUIT is OTHELLO and what together?
The "what" is of course a sit down game!
Could be more than one answers.
Ok, So I think I have the pattern and a possible answer
You add up all the spaces on the playing board, 42 in connect4, 24 in backgammon (24 backwards is 42 so it works) 64 in othello, 40 in monopoly(24 + 40 = 64 it still works) and 73 in trivial pursuit. So a possible answer could be tic tac toe(73 - 64 = 9 and tic tac toe has nine squares)?