incorrect spellings - how do I approach this?

[SansaClegane]

DS1 is in Year 2 and has weekly spelling tests.
Last week, it was all about words ending in -ful e.g. beautiful, cheerful. So I looked in his spellings book and there was a sentence: "Don't speak with your mouth full, it's not very graceful". Now this is how DS wrote it; but 'mouth full' had been marked as a mistake. Now I get that his word to learn was 'mouthful', but surely in this context, the way he wrote it is correct?
Then I looked at his new words to learn for next week, and they are all numbers written in full. However, they are written in his spellings book like this: 'Ninety four', 'forty five', and so on. Unless there is a new rule that has passed me by, shouldn't all numbers between 21-99 be hyphenated when written out?
I'd loathe to teach him to write it the wrong way, but also don't want him to come home with a test full of 'mistakes' because of this.
So, how do I approach the teacher about this without appearing rude? I'm also not sure if I can do this at the door at pick-up time with all the other parents around? Has anyone been in a similar situation? Any advice appreciated!

Without a crystal ball I'm unable to predict what any child will need to know in the future. However any child planning on going to university will need to know how to correctly write numbers as evidenced by Fergusons link.

Sansa, my son's school told the parents in a meeting to firstly focus on getting the letters correct and when that was solid I can remind them about the hyphens in numbers.

I didn't mean to say 'spellings' mrz. I know what you mean!

I think all you can do is look closely at letters and homework. Some errors may not be the teacher, they could be from a TA or the office. Some mistakes will be careless typos and then there are others which are just wrong.

I remind my kids that we are far from perfect and we all have different strengths....and that the teacher must have been so tired to have forgotten the difference between you're and your or they're and their again.

It's always easier to learn the correct way first than try to unlearn later