You can put this solution on YOUR website! Not matter as long as you can generalize a bit and understand that an even number is divisible by two, and with remainder of zero. Odd and even numbers are always integers.
If n is an integer, then 2n+1 is ODD.
Let k, m, p, be any integers also. is sum of three ODD integers.
Look at each part of this sum. is even. 3 is odd.
Adding odd number to an even number gives an odd sum.
This is EVEN+ODD=ODD.