### Divisibility & Induction

Problem requiring decisions

## Suggestion

A magic square is a square grid in which the numbers in each row, column and diagonal sum to the same number.

For example,

is a magic square that uses each of the numbers from $1$ to $16$ once.

There are many of magic squares of different sizes; perhaps you have come across some. The artist Albrecht Dürer even included one in his engraving Melancholia I.

But why are magic squares about addition? Could we have a magic square where the numbers in each row, column and diagonal multiply to the same number?

Suppose we have a $7$ in a row of a multiplication magic square. What does that tell us?