[Illustration:
+---+---+---+
| 1 | 9 | 2 |
+---+---+---+
| 3 | 8 | 4 |
+---+---+---+
| 5 | 7 | 6 |
+---+---+---+
]
It will be seen in the diagram that we have so arranged the nine digits
in a square that the number in the second row is twice that in the first
row, and the number in the bottom row three times that in the top row.
There are three other ways of arranging the digits so as to produce the
same result. Can you find them?