How can you tell if a guy likes you in 5 grade but tries to hide his crush?

You should pay a little bit of attention to him and his actions. Usually if a guy likes you, he might look at you a lot, blush when the two of you make eye contact, etc. If you like this guy then you should be yourself around him. If he really does like you he will like you for ho you really are. Try to talk to him and hang out with him more (ONLY IF YOU LIKE HIM). This will help him become more confident around you and he could ask you out ( boyfriend and girlfriend wise).