Take a quick moment to sit down with the student that is not getting even and odd and explain it this way.
First write out a ridiculously long number with all even digits except for the ones place:
Ask them quickly is it even or odd? Tell them you should know instantly. All you need to do is look in the ones place. Ask them where the ones place is. Have them show you. Now explain that the number in the ones place is the key number they need to look at.
Now ask them if 9 is even or odd. Give them the poster and explain that even is when you have a partner and odd is when you do not. Use the poster to help explain this. If you must, you can use manipulatives as well.
Tell them it is easy to remember evens with the chant "0, 2, 4, 6, 8, let's celebrate evens." And all the rest are odd.
Have them go through the exercises on the sheet. By the end, they will tell you they now LOVE even and odd numbers.
Presto, student confidence is back!
Please share this with everyone you know! It was very helpful for my second grader to understand the concept after using the script I outlined!