Demo Lesson Idea thoughts and suggestions!

Hi everyone! I am doing my first ever demo lesson in 1st grade on Friday afternoon (last day of school end of day I’m nervous LOL) and only have 15-20 minutes for it
I was given the option to do ELA or math
I feel like math would be easier given the time constraint and it being the last day of school it can be way more interactive and engaging

Would doing a greater than less than activity work?
I’m thinking of putting them in groups and having cards and they essentially are playing “war” and writing down their 2 digit numbers and comparing them

5 mins of overview aka the explicit instruction and going over objective

5-7 minutes of the activity as I assume it won’t take that long and don’t want them to finish and act up from boredom

5 minutes or little bit more of a wrap up