Is it possible to restrict submissions based on an entered value?

Hello!

I am creating a form for families to register their children for a week long event. I would like to create a condition whereby if a family attempts to register a child who is younger than 5 OR older than 11 then a message will show up reminding them that registration is only for children ages 5-11. 

Is that possible? 

Thanks much! 

You could add a text message to let your user know the entered age cannot be less than 5 or greater than 11. 

Then following a condition will help you to show the text message when entering an incorrect age: 

Here's also a guide that will help you to show fields based on user's answer: https://www.jotform.com/help/316-How-to-Show-or-Hide-Fields-Base-on-User-s-Answer 

Hope this helps.