The significance of understanding whether an answer is going to be odd or even is not often instantly understood. If children understand this, they will have an instant way to know whether their answer may be wrong. They will know that 459+243 has to be even because they are both odd numbers. It develops numbers sense. That’s a good thing!
After watching this free math video, I see how I could have done things a little better. Writing all even numbers in red and odd numbers in black would have helped tie in the Cuisenaire Rods to the symbols. Our numerals themselves show no similarity to quantities (what does the shape of a 5 have to do with five things?) so bridging that gap with colors or letters to indicate odd or even would be a good idea.