Answer:
Let a and b integers and suppose that are even numbers. Then, exist integers k and m such that [tex]a=2k[/tex] and [tex]b=2m[/tex].
Then,
[tex]a+b=2k+2m=2(k+m)=2n[/tex]
Since, k and m are integers then n=k+m is an integer. Then, since a + b is of the form 2 by an integer n, then a + b is an even number.
