"You can't make any conclusion from the 'if' statement, about the difference of two odd integers." That's what I said.
I tried to see if we could, from the equation "2m + 2n = 2(m + n)", have any equation of "m – n" (m and n being two odd integers here), but all I got was the truism "m + n = m + n".
Solving the prompt with the new information given by fellow stack users
(Another correction: The result is 2(m – n); made a bad calculation there)
Best Answer
Each odd integer $m$ can be represented by $m=2 m'+1$ (or equivanent $m'=\frac{m-1}2$).
Thus the difference of two odd integers is $m-n=(2 m'+1)-(2n'+1)=2(m'-n')$. This is even for any numbers $m, n$.