It's the 9th, but it's not September

Notes:

It's easy to get confused. If you use the DD/MM format, you get 9/5. If you use the MM/DD format, you get 5/9. As for me, it's my birthday, to which I often received no end of ribbing from my ex-USSR friends for being born on "Victory Day."

Maybe I'll share some cake with Cirno to make up for her confusion.