Big one is upvotes I guess? Or not… It correlates only sometimes. The small one I have absolutely no idea.
Edit: Thanks everyone for answering! The big one is upvote rating and the second one is time. Regarding no letters: My guess is - it doesn’t show “m” or “h” near the time because my system is not in english, and though most of the lemmy is in english, for some reason the time on a post renders only “sometimes” in my system language or doesn’t render at all.
The big number is the “karma” value. Upvotes minus downvotes. I’m not sure why the small number doesn’t have a letter next to it. For me, it’s how long it’s been since the comment or post.