m+n为偶数,n+P为偶数所以,(m+n)+(n+p)为偶数(m+n)+(n+p)=m+p+2n为偶数2n为偶数,且m,n,p为整数所以m+p为偶数.反证：m+p为奇数n为整数,2n为偶数m+p+2n 为奇数m+n+n+p为奇数m,n,p为整数m+n与n+p必有一个是奇数与原题意...