Students played a game of Battleship against me. Using a coordinate plane, I highlighted four ships. One in each quadrant. Then, students had to guess an ordered pair. If it was a miss they plotted a black dot. If it was a hit they plotted a red dot. I told them that the "ships" would be a minimum of three and the maximum of six.
Then, students got a copy of their own coordinate plane and plotted four ships. One in each quadrant. Working with a partner, they tried to play their own game!