"It is not my glove."
Translation:Det är inte min handske.
Why is this "min" rather than "mitt"? Shouldn't it be the same as "Det"? (otherwise it'd be Den)
Handske is common gender, thus, you would use min to refer to the 1st person singular possessive (i.e. "mine").
"How do you know which “it” to use? If “it” refers back to a word in a preceding sentence, you use den to replace en-words and det to replace ett-words.
If “it” does not refer to a preceding word (as in “It is raining today”), we always use “det” (which would be “Det regnar i dag”).
We also use "det" in the phrase "there is/are" (which would be "Det finns" in Swedish)."
(copied from the bottom of the page here: https://www.duolingo.com/skill/sv/Pronouns-objective)
Have a look here, I wrote a little about that: https://forum.duolingo.com/comment/26420394/Answers-to-some-common-questions-on-grammar-that-beginners-have
Yes, they're synonymous but ej is formal, typically used in formal text and where brevity is important (e.g. road signs).
No, putting the inte at the end would be like putting the "not" at the end in English, and handskar is the plural form.