Question 476562
{{{(2n)^2 = 4n^2 = 2(2n^2)}}}, so the square of an even number is always even.

{{{(2n+1)^2 = 4n^2 + 4n + 1 = 2(2n^2 + 2n) + 1}}}, so the square of an odd number is always odd.