Testing if there is an entity with a objective score lower than another objective score

Say there is a player called Dave with a Health score of 10 and a MaxHealth score of 20. I need to check if there is any players with a health score lower than MaxHealth and tellraw it. Also is there a way to add values onto Health say 60 or 20 but without it going over MaxHealth? E.G. Health + 60 = MaxHealth (without going over)? Thanks in advance.