I have no idea how you or your parent immediately arrived at calendar dates (which in my book require a period at the end), but to everyone i know, 1.10 is not a date, but a floating point number with the same magnitude as 1.1, which is thus closer to 0 than 1.9 is.

What locale is that? I know that e.g. de-DE uses trailing dot to mark ordinal numbers, so "1." means "the first", but it also uses decimal comma instead of decimal point, so there is no confusion.

TBH, I'm German, but a Software Engineer, so it's a mix of both.

I don't know what an average German would make of "1.10", really. I've only seen that as "subsection 10 of section 1 of a book".

How would October 1st be written down at your place?

1.10.

Ah i see, the trailing dot.