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.