+---+---+---+
| 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?


78.--ODD AND EVEN DIGITS.

The odd digits, 1, 3, 5, 7, and 9, add up 25, while the even figures, 2,
4, 6, and 8, only add up 20. Arrange these figures so that the odd ones
and the even ones add up alike. Complex and improper fractions and
recurring decimals are not allowed.


79.--THE LOCKERS PUZZLE.

[Illustration: