In his Priceless Memories book, Bob gave a short description of Lucky Pair, which he claimed was an idea of his mother's.
"Lucky Pair was a board game played by two contestants. The contestant who completed the most pairs won the game. To complete a pair, you had to match two squares on the board. A contestant chose a number on the board, and the square turned around, and perhaps it might reveal "1492." The contestant would say "Columbus discovered America," and complete a pair. But suppose a square revealed "Civil War General" and the contestant said "Robert E. Lee" and the square turned back into place. That was not the answer we were looking for - the pair was not completed. Now, the contestant should try to remember the number of the "Civil War General" square in case he discovers the the square that reads "General James Longstreet." Think about it for a moment. Lucky Pair offered endless possibilities that were a lot of fun."
So it appears that, like suggested above, there was a Concentration element. A player could score a match by finding one element of the Lucky Pair and correctly guessing what the other element would be, or you could score by finding the two numbers on the board that completed the pre-determined information on the pair. Now this sounds pretty good. I wonder, in the case of the 1492 example above, whether the square that contained "Columbus discovered America" was automatically removed from the board, or did it remain to louse up attempts at future matches?
