On the board I have drawn a 5 by 5 grid. I've written 1 number fact (ex. 8x9) in each square and have covered each square with a piece of card so the question can't be seen. I divide the class into 2 or 3 teams. Children take turns removing a card and answering the question. If they get it correct they put an X across it. Each team has a different symbol. If the person gets the answer wrong the question gets covered again and play goes on to the next team. The first team to connect 4 correct answers in a row, column or diagonally wins. Extension -- sometimes I use fact families instead of having the actual answer given.