Plus or Minus

Plus or Minus is a game to help children master the arithmetic operations of addition and subtraction. A 5 x 5 grid is supplied. The rows each total the answers at the bottom, the columns each total the answers on the right, and the bottom row, the right-hand column and the diagonal all total the answer in the bottom right-hand corner, which is left blank. Children must place a plus or a minus sign in front of each number to make the rows and columns add up correctly.