How To Play: Add 1-19 to the intersection designated by the board, so that the sum of four digits on the longitudinal, transverse and diagonal lines is equal to 38. Play Instructions: 1-19 digits 6 side row building blocks 19, arranges the number, the building block connects into 15 straight line. To make the sum of the block numbers 38 on each line. OPEN MIND - This number puzzles can train one's ability to think and respond quickly. At the same time can cultivate children's interest in mathematics.