(Investigator 102, 2005 May)
Are "magic numbers" either
The following is a so-called "Magic Square":
The sum to which the rows, columns and diagonals each add up, is said to be the "magic number". In the example above the magic number is 15.
Magic squares originated in India or China thousands of years ago. Emperor Yu of China is said to have discovered the various patterns of the 3 x 3 square near BC 2200.
Magic squares reached Europe via the Muslims and were constructed in Europe by the 14th century.
To work out the "magic number" quickly, use the formula
(N2 + N) / 2L
where N is the total number of "cells" and L is the number of cells in one row or column. (Note there is actually no 2 x 2 magic square although the formula gives a magic number "5".)
Long ago magic squares acquired the "magical" description and many people believe that "magic numbers" had magic powers. They, therefore, wore magic numbers or magic squares on a chain around their neck.
American statesman and
Franklin (1706-1790) amused himself, when he became a clerk in 1736 for
the Pennsylvania General Assembly, by making up magic squares. He later
There are, however, systematic procedures to work out what numbers go in what cells. For Franklin to fill in magic squares quickly he must have known about such procedures. Frenchman Antoine de la Loubere visited Siam in 1687-1688 and there learned a method for filling out magic squares that have an odd number of cells. It’s described in the book by David Stern and I won’t repeat it here.
Another method starts by
working out all
the ways or combinations that get us the "magic number". For the 3 x 3
square, where the magic number is 15, the different combinations are:
Note the number "5" occurs four times. Therefore "5" must be positioned in the only cell used on four occasions – i.e. the second row and second column and both diagonals. So, "5" goes in the centre.
Corner cells are used on three occasions that is in one column, one row and one diagonal. Therefore, in the four corners we put the numbers used on three occasions, these being "2", "4", "6" and "8". The rest is easy.
(Investigator 103, 2005 July)
As a child I spent many hours playing around with magic squares. There were several formulae I used to know for constructing them.
There was one square I loved because it arrived at the number 78 (allegedly a Moorish Musselman's mystic number) in twenty three different combinations.