I hate them… And a special place in hell for 十日 because it’s not just plain weird but also requires とおか and I sometimes write it as とうか.
The good news is when speaking 「十日」 it doesn’t matter if you say 「とおか」or「とうか」！
It’s just the kun’yomi for 10. Same with the other words you mention. It’s no more weird than 七日 or 七つ which also use kun’yomi for the number. Same with 一つ, 二つ, etc.
Edit to add:
I’d suggest maybe looking over the chart of on vs kun readings for numbers on this wiki page:
It might help make some of these counters make more sense.
Keep on going with the reviews. Eventually they will sink in.
I was the exact same but now I haven’t got them wrong in quite some time, trust me let the srs system take its course and you will soon get them. (also 十日 was the one I used to get wrong all the time too)
For some reason the other examples you listed seem “easier”. But yeah, at some point they will stick for real… I hope
If anyone has any memorizing trick for when とう and とお appear please share haha, because I also always get them mixed up and it’s super frustrating!
You basically won’t ever come across とお. I can’t think of any cases where it shows up aside from 十日 and 通.
Nono, it’s definitely more weird. 日 makes things utterly weird. It’s absolutely without a doubt the weirdest of all the counters.
七日 is なのか, which is literally the only time the なの reading of 七 is used, ever.
Aye, @nicolasrdiaz, in general, for any of the long-o sounds, it’s basically always ～おう except for the handful of cases where it’s not, so it’s simple to just remember those exceptions.
And then 4日 is yokka but 8日 is youka
If they appear as a contained reading in a kanji (as in, not something like 問う where the う falls outside the kanji), then generally the thing with う would generally be an onyomi, and the thing with お would generally be a kunyomi. Even though things like おう and おお, こう and こお, とう and とお sound identical to each other, the spelling differences are preserving their origins in the language.
It’s not that weird if you know how the language evolved.
I put how I remember them here: 四日 and 八日
4日 is easy for me because the ん in よん logically gets garbled into the double consonant. But 8日 is hard because it’s ようか whereas 八つ is やっつ.
I just thought 八日 totally must be はつか… Well no, that was another one of my number friend. So, down to Apprentice 3 for八日
I wouldn’t really call this a ‘trick’, but I kinda force a pronunciation difference to exist in my head even though it’s almost impossible to hear in real life. You know how blocks like 人を are technically pronounced ‘hito o’ (two ‘o’ sounds), but they come out as ‘hito–’ in fast speech? I do the same thing with words like 遠い（とおい). I pronounce the と, and then I immediately make an お sound. It’s basically indistinguishable aurally (you won’t hear much of a difference), but the spelling difference goes into muscle memory because your mouth and throat muscles will move into position in order to make another ‘o’ sound. This approach is also historically accurate in the sense that a lot of the おお sounds used to be written おほ or おを, meaning that they really were pronounced as separate syllables at some point. For とう, I just drag the vowel sound out. No additional mouth and throat movements.