[Illustration:
SUBTRACTING DIVIDING
11 4 14 13 36 8 54 27
16 7 1 2 216 12 1 2
6 5 3 12 6 3 4 72
9 19 8 15 9 18 24 108
]
The first, by subtracting, has a constant 8, and the associated pairs
all have a difference of 4. The second square, by dividing, has a
constant 9, and all the associated pairs produce 3 by division. These
are two remarkable and instructive squares.