EYFS Interview observation help.

Hi,
I have a lesson observation coming up for a reception teacher post. It is for 30 reception children and I can do maths or literacy, the children are said to be 40-60 secure, emerging ELG. Observation is 20 mins, so I am thinking of putting in the planning what my adult led activities would be. I'm currently going round in circles with what I want to do!
My current idea is ordering numbers.
Introduce myself then start with a number recognition game using Interactive White Board.
Main input- ordering numbers on a washing line. Ask children what comes next, can they select the correct number. Some numbers missing can they write the number. I am thinking of ordering to 20, as looking at the schools plan this is what they are focusing on at the moment.
Plenary- thumbs up thumbs down for if they have met learning objective.
I just don't know if I am over complicating it and I keep changing my idea. I know there current topic is once upon a time and looks like they are reading traditional tales. So I am thinking maths will be the better area so I don't choose the same book they have already read.
Can anyone let me know if they think this will work? Or have any better ideas I'm beginning to stress now.

Thank you.

 

Am doing this just at the moment so much of what you are thinking is just fine! Make sure you give an outline of what you may put as continuous provision to facilitate this learning in different situations.
Consider how you will engage all children when on the carpet, what about those who are not recognising numbers to 10 yet?
Will you begin by orally counting to 20? Will you flash card the numbers with chn first to see how well they recognise them?
Not saying you should do these things just making you think out all options.

Hope all goes well let us know if you get the post!