Question

Prove: The square of an even number is even

Answer 1

• Squares of even numbers are even, and are divisible by 4, since (2n)2 = 4n2. Squares of odd numbers are odd, and are congruent to 1 modulo 8, since (2n + 1)2 = 4n(n + 1) + 1, and n(n + 1) is always even.