Question

If m and n are odd positive integers, then m2
+n2is even but not divisible by 4. Justify

Answer 1

hope this will help you

Answer 2

this is because 2m+2n =2(m+n) which is always even as an even number is one which can be divided by 2. but the part which says 2m+2n is not divisible by 4 not exactly true.
For example,3and 5are two odd numbers.
but 2*3+2*5=16 which is divisible
by 4.
(this was what I understood from your question)
I hope this was the answer you were looking for.