Not a teacher
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The way dates are written in English is confusing, especially to foreigners and learners alike. The fact that [month]/[day] and [day]/[month] coexist, with no additional clue to help distinguish which format it is, has caused more problems than I can count, seriously. While seeing a 4/30 isn't that big of a deal—there are no 30 months, so it's obvious the format used is [month]/[day]—encountering something like 11/12 can baffle the person, or even worse, cause legal issues.
I remember how back when I worked as a receptionist as a teenager, my new manager stormed in, yelling that I'd made a mistake in an invoice because the date on it didn't agree with the date on the receipt printed by the register. The program we used for invoices used the [day]/[month] format, but the register was manufactured in the US and used the [month]/[day] format. It was moderately fun(ny) to explain it to my new manager, especially given they were a rather apodictic person that didn't take it all that well that their subordinate knew more about their system than them themself. Good times.
But the confusion doesn't stop there. The "laziness" of humans makes them omit certain parts when writing things.
The thirtieth of April → The 30th of April → 30th April → 30 April.
Many learners here in Poland read and pronounce it as they see it, thirtieth April or thirty April, both incorrect. The omission of of, st, nd, rd, th is directly to blame here. While we omit it in writing, we never omit it in speech. For this reason, you might want to be a fussy teacher and tell your students to write it exactly as it's pronounced, the thirtieth of April. Not only will it get rid of the confusion caused by [month]/[day] vs [day]/[month], but it will also be a nice way of practicing spelling and drilling how to actually say it in speech.
Having said all of that, I personally use just the number, with no st, nd, rd, th or superscript, and the first three letters of the name of the month.
30 Apr
13 May
27 Jun
17 Jul
etc.
