So in real darts there's a variation on the standard game called "Around the clock". In this version you still throw 3 darts per player per turn, however you must start by trying to hit the number 1. When you hit 1 you'll move on to 2 etc.sequentially all the way up to 20. When you've hit 20 you have to finish on a bullseye (first to finish wins). Usually the double and triple zones don't count (so if you hit them you have to throw at that number again), but I've played versions where the double and triple lets you jump 1 or 2 numbers correspondingly which I feel is quite interesting because the person in the lead can't just chill and cruise along.

I believe this version can be quite good training because you must aim for a very specific section at a time, but you'll get a chance to aim at all angles throughout the game. And no maths! lol