Question from Belinda, a parent:

My son came home with a math question that I can figure out. He needs to use only the number 4 and only four 4's, no less no more.
The problems need the answers 11,13,14,and 18. He can use any mathematical sign except square root. He's been able to get all but these
so far and I've worked them, but can't come up with the problems. Can anyone help?

Thank You!
Belinda