The "vs mode" of this game is a genuinely great time. It's effectively a game of calculating a certain number on a calculator faster than your opponent can, except that the numbers and signs are all over the place and you have to navigate everything by controlling Donkey Kong Jr. from the game Donkey Kong Jr. for the NES and Arcade.

It's jank. It's trash. It's perfect.

I am Donkey Kong Jr. Math's strongest defender.

Donkey Kong Jr. Math is an edutainment title for the NES, when Nintendo tried to appeal to the parents by releasing this game to teach children math. It didn't go well to say the least, resulting in Donkey Kong music game being cancelled, and this is the only released game that has "Education Series" label. As a game, there's little reason to play this nowdays, however I don't think it's the worst thing ever. I can see multiplayer being fun. I also think this is a case, where retroachievements has elevated my perception of this game slightly. Going for highest score in excercises can be quite challenging, almost feeling like you have to speedrun it. Of course with modern emulation technologies you can cheese it, but y'know. That being said, I'm not going to say this is a hidden gem or anything. This is still a rather basic edutainment game, of which you can find much better alternatives nowdays.

Uhhh this kind of rules?

Look, I have no delusions about being cool. When I was a kid, my dad was getting his PhD until I was like 9 years old, so I often found myself killing time in empty classrooms on Oklahoma University campus. That meant 30-60 minutes of just me and some chalkboards. For most kids, I assume that would mean a whole bunch of doodling. But for this radical 90s youth, it meant coming up with the most complicated long division problems I could and seeing how fast I could solve them.

I think basic math is fun! Sue me! My wife and I often watch 8 Out of 10 Cats Does Countdown and compete with each other for points throughout the episode. The 2-player mode of DK Jr. Math gave me the same vibes, but with some NES jank thrown in, and being limited to using single-digit numbers for each step of your equation. I had a great time!

The single-player mode was extremely anxiety-inducing at first while I tried to figure out if I remembered how to do this kind of math without being able to write down remainders, but once I got the hang of it, I knew this was exactly the kind of edutainment that little Alex would have loved. This is absolutely not for everyone, but tiny geeks and nerds (both currently and formerly tiny) will have a blast.

In the early days of the Famicom, Nintendo was eager to sell their game console as more than just a toy, but as a real Computer for all the Family. There was Family BASIC for all your serious computer needs, Mahjong for dad, and of course edutainment for the young kids! In the end, that angle wasn't much of a success (except for good old Mahjong) and Nintendo's educational series was short-lived with only two games released (Donkey Kong Jr. Maths & Popeye no Eigo Asobi) and a third cancelled (Donkey Kong no Ongaku Asobi).

I don't think Nintendo had much faith in those things beyond "your kids can also learn maths and english on our video game console", since they're obviously half-assed: basically educational content slapped on well-known classic games.
In the case of Donkey Kong Jr., you do maths by... Grabbing vines? Yeah, there's not much meaning to it.

Surprisingly enough, the two main modes are multiplayers only (as if that thing wasn't niche enough). Time for you to compete with your friend in intense arithmetic battles, well, if you manage to convince a friend to play Donkey Kong Jr. Maths with you (spoiler: it's not going to happen).
Last mode at least is single player, but it's probably even less fun. You've got operations to solve, and you need to answer by... Grabbing vines. It controls quite horribly and any parent who forced their kids to do divisions and multiplications on that thing should have been charged for abuse. Also... Why not just use pen and paper instead? What's the point of it, seriously? Awful.

A curiosity, but not much worth a look even for fans of Nintendo oddities.