The puzzles in this book are based on 5 by 5 pandiagonal magic squares. A pandiagonal magic square has 20 sums to the same number. Each row, each column, each of 5 downward diagonals, and each of 5 upward diagonals sum to the same number, called the magic sum. The four following charts show the 5 rows, the 5 columns, the 5 downward diagonals, and the 5 upward diagonals. The rows, columns, and diagonals will be illustrated using the following magic square. Incidentally, all entries in this magic square are prime integers. 5 103 16067 19 1493 17 1489 17 101 16063 113 16061 13 1487 13 1483 11 109 16073 11 16069 23 1481 7 107 The 5 rows: