If $m$ and $n$ are odd integers, how many terms in the expansion of $(m+n)^6$ are odd?
odd + odd is always equal to even when an even number rise to an even number is always even then the answer is none of the turns is odd.
The terms are
m^6 + 6m^5n + 15m^4n^2 + 20n^3n^3 + 15m^2n^4 + 6mn^5 + n^6
The terms in red are odd
+428 
