Choose any two odd numbers and one even number, such as 3, 5 and 2.
How would you like to represent these numbers?
Try adding them together and draw/make the representation of their sum.
What do you notice about the answer?
Look closely at your model.
Would it work in exactly the same way if you used different numbers but still two odds and one even?
Can you use your example to prove what will happen every time you add two odd numbers and one even number?
See if you can explain this to someone else. Are they convinced by your argument?
Once you can convince someone else, see if you can find a way to show the argument on paper. You might draw something or take a photo of things you have used to prove that your result is always true from your example.