I'm not a parent, but I am a former 10-year-old child who liked math and (would have, if it were around) liked Minecraft! (And I liked math so much from that age that I got my degree in it!) I don't really have an answer to the actual question (but I'll still give it a shot from this perspective later), but I nonetheless wanted to speak to what might be your ten-year-old's experience. There are many, many diverse ways you can build on (and out from) your 10-year-old's existing interests! So, this "answer" will be primarily about how you can help your son grow his existing interests into deeper ones—and, as you'll see, into new and neighboring ones too! Maths (and even minecraft) are not a monolith, and there are so many different ways to engage with them and grow them into new and exciting things.
What follows is a very long answer about possible ways to encourage and explore your son's existing interests. I didn't realize this would be so long when I started—whoops! But I suppose it's a testament to how rich your son's interests already are, and how many ways they could grow.
Through no fault of their own, my parents (both of whom are not very mathematical) had trouble finding ways to engage with and feed my interest in math. I'm not sure if you're in the same situation as them, but just in case, I wanted to offer some resources that might both help your son dive into math and broaden his interest outside of it. Depending on why your son likes math, there might be different routes to take. I've heard that One, Two, Three...Infinity is a classic, and a wonderful introduction to many interesting mathematical concepts. (Sadly, I didn't hear about it until I was familiar with everything in it, but I know lots of people for whom this was the book that really got them into math.)
For me, though maybe a couple years after I was 10, I got entranced by Gödel, Escher, Bach: An Eternal Golden Braid. It's a thoroughly readable but deep introduction to what makes math (and thought, and language) tick, and explores these deep questions in a fun and interdisciplinary way, weaving together (as you'd expect from the title) Escher's artwork, Bach's musical techniques, and logical systems into an integrated piece of literature. Each chapter is prefaced by a fictional dialogue between Achilles and the Tortoise of Zeno's paradox, patterned after a similar dialogue by C.S. Lewis (which is included in the book!).
Also great—especially for the ability to re-engage with different puzzles at different times—are Martin Gardner's recreational math puzzles. They're usually accessible to just about anyone and don't require prior knowledge of math, but looking back, I can say that they still manage to get the reader engaged with real mathematical concepts, even if the reader doesn't always realize it! I recently received The Colossal Book Of Mathematics, a compilation of puzzles, and each chapter is a nice self-contained piece.
I'd also recommend the YouTube channel (and associated webpage) 3Blue1Brown by Grant Sanderson for videos and interactive lessons that introduce particular math topics with beautiful visuals and clear narratives. Other popular books like Chaos by James Gleick might be of interest (fractals always compel!).
There are many fields within math that you might want to introduce your son to, which don't necessarily require prerequisites, depending on the presentation: graph theory, abstract algebra, linear algebra, transfinite arithmetic (infinities), cellular automata, etc. It's all about finding the right presentation: even if something seems very formal and esoteric, there's usually a way to start a 10-year-old thinking about the underlying questions. It might be good to introduce your son to resources that introduce their topic alongside basic set theory—set theory makes talking about everything easier, and many mathematicians will use the terminology without thinking. Dealing with infinities is actually a good intro, hence One, Two, Three...Infinity, since it's just about counting, and introduces you to set theory terminology along the way! But don't feel like you have to wait before introducing your son to every new field of math. For example, graph theory puzzles can be posed and thought about without almost any formal introduction—in fact, that's how the field began! In general, Dover publications has great, classic books of many different levels of prior knowledge for usually between $10 and $30.
By the way, if your son likes math, then depending on what about it he likes, he might also like physics! Eventually, The Feynman Lectures On Physics might be good entry point to keep in mind once your son has the mathematical prerequisite knowledge. In the meantime, popular accounts of physics via science channel or discovery channel, e.g. Wonders Of The Universe, are accessible tastes of the exciting kinds of things physics is about. There are loads of other scientific branch-off points from math (though physics is probably the most connected): biology, chemistry, electrical engineering, geology, astronomy, etc. Each of these has presentations and introductions that are accessible to any 10 year old—all that's needed is interest!
Okay, this is a major one: does your son enjoy building complicated redstone circuits and mechanisms in Minecraft? If so, he might enjoy computer programming! There are so many ways to go here. Computer programming is about as diverse as writing itself. Different languages and interfaces provide different ways of approaching it. Further, information on how to do it is more accessible than ever—the problem now is sifting through all of it. There are so many introductions to coding for kids—just google! And some of them tie directly into Minecraft: you can actually code up your own mods for Minecraft, which lets you alter the gameplay itself in any way you can dream up. It's incredibly creative. Some "starter" languages might be Haskell (specifically via Learn You A Haskell For Great Good!), Python, or even, because of its ease of use, great documentation, and connection to math, Wolfram Mathematica. Of these, only Mathematica is proprietary (unfortunately), but it's not really proprietary: you can use it at full functionality, for free (after signing up for a free account) online here.; there are also puzzles to try and demonstrations. Only the desktop version is proprietary.
Also check out Processing, a language for creating graphics and animations. It lets you really see what your code is doing! And this gives your son the opportunity to simultaneously make art and engage with what might be an existing interest.
There are also tools that let your son make his own video games, which might be of interest. There are some low- or no-code opportunities, I think, (maybe GameMaker Studio 2?) but if your son does get into coding and/or digital art, consider introducing him to Unreal Engine, Unity, Godot, and more.
Finally, let me mention something a bit off the wall in this vein: speedrunning. If you're not familiar, speedrunning is when someone tries to complete a video game as fast as possible. Surprisingly, this simple goal drives people to such great problem-solving lengths that even explaining how a certain glitch works can take roughly the same length as a lecture—and with about as much technical content. People will literally reverse-engineer the game code to figure out how it works—all for shaving a few fractions of a second off gameplay time. It's very creative, very impressive, and very watchable—there's a whole genre of youtube video that consists of people presenting what happened in a narrative and exciting, but still informative, way. SummoningSalt is a good introductory channel to the kinds of things that can be done; here's an example of a highly technical Paper Mario: The Thousand Year Door tool-assisted playthrough; here's the first part of an hour-and-a-half deep dive documentary into how a certain speedrunner endeavored to play Super Mario 64 with as few A presses as possible (which is a type of speedrun, except instead of minimizing time we minimize A presses! here's a channel focusing on novel speedruns of that ilk), and here's a classic example of that speedrunner explaining the strategy for a single level (which by itself is almost half an hour!); here's a video about how some speedrunners trained a genetic algorithm to play a certain part of Paper Mario, and here's how even Minecraft can be speedrun. I would actually be surprised if your son wasn't already aware of speedrunning—Minecraft speedrunners are huge right now. And it's very compatible with interest in math and computer science. If your son expresses interest in performing his own speedruns or, especially, tool-assisted speedruns, he might need special hardware or software to do so (e.g. an adapter to connect a gaming controller to a computer), and this could be very rewarding! Your son would likely learn a lot about computing and problem-solving in general.
If you have any further questions about intros to math, physics, or computing, let me know! I obviously know nothing about why your son is interested in math, so I'm kind of just saying everything that might be relevant. I of course don't know if you or your son already know about all of these things—maybe you do! But I would have loved to know about and have access to these resources.
I guess this went on a little longer than I expected it to...! But all I will say on the actual question (which seems as though it might mirror what others are saying) is based on my experience with communication in general, which is that humans often behave "paradoxically". If you encourage someone to do something that they don't already want to do, they might actually form resistance to doing it and push back. Directly encouraging someone can actually, in effect, have the effect of discouraging them! If you want to "broaden someone's horizons", then in my estimation, it's often better to just provide them with the opportunity, but not suggest that you think they should do it or, worse, that you think they should enjoy it! The thing here is that there are no guarantees. There's no way to know if that person will take up that opportunity, or that they'll enjoy it the way you do. And that's okay. There shouldn't be any guarantees. People are going to follow what interests them, and when we're talking just about personal interests and enjoyment, that's exactly what they should do. The things they do that align with their interests will be far more amazing (and personally rewarding to them!) than the things they do that don't.
Sure, there is a level of familiarity that someone needs to have with a subject or activity before they dismiss it as uninteresting; if your ten-year-old doesn't realize this yet, my guess is that he'll still have plenty of time to do so on his own—and that there might well be more effective ways to communicate this outlook to him than by simply encouraging him to do something you think he'll like and hoping he winds up doing it and liking it. As a kid, I did always find the "you don't know until you try" argument pretty unconvincing, though. Looking back, I think it might have been seeing people try things that they themselves weren't sure of, and then seeing that they still valued the experience for what they learned from it (even if they didn't like it), which let me know that openness to new experiences is useful. But, of course, being open to new experiences doesn't mean you'll always pursue them further—once you've tried them, you might, after all, decide you don't like them. Yet since this is still valuable, I think it's just as important to support well-informed negative decisions about pursuing something as to support positive ones. My guess is that ten-year-olds, being people as well, will tend to feel similarly—but I'm not a parent!
Best of luck, and I hope this perspective—and these resources!—are at least a little useful. And if not now—as I'm not totally sure what your son is ready for, material-wise, so to speak—then maybe in the future! :)