## The Magic Square

A **magic square** is a square grid of numbers, in which each number appears
once and the numbers in each row, column, and the two main diagonals sum to the
same value. The most common magic square uses consecutive integers from 1 to *n*,
where *n* is the number of cells in the square.

Try your hand at completing a magic square. In the grid below, insert the numbers
from 1 to 9 (each only once) in the yellow squares, so that the sum of each row, column,
and the two main diagonals is 15 (their sums are shown in the white squares). If you're stuck,
click the **Solve It** button. To reset the grid, click the **Restart** button.