HÉ Pok, keeping all those languages going requires quite a lot of magic, congratulations :-))
"Εγώ δεν χρησημοποιώ μαγικά" actually translates to "I do not use magic tricks". " I do not use magic" translates to "Εγώ δεν χρησημοποιώ μαγεία"
Μαγικά does not necessarily mean magic tricks. There is also the greek word μάγια synonymous with μαγικά, which also refers to magic as an energy and has nothing to do with tricks (as in, tricks a magician would be performing on a stage) :P
μαγικά could be translated as magic spells. Magic tricks is usually translated as μαγικά κόλπα!
For those interested, magic tricks is "μαγικά τρικ" in Greek. Easy peasy :)
I think the lesson is that Greek uses a plural noun where English uses what might be called a "collective" noun. It does bother me that we're asked to learn the word without the article and to determine the gender and singular form (if any) from the plural form. I'm trying to "take notes" as I learn vocabulary but all I've learned here is that I don't need gender or number to learn this expression.
Well, it's not that hard to deyermine the gender in this case. If a word ends in -ικά and it isn't a first name (Ναυσικά, for example), chances are that it's neuter plural. :P
Neuter plural is used often in phrases like Διαβάζω αστυνομικά (βιβλία), Βλέπω αθλητικά (νέα), Βλέπω παιδικά (προγράμματα), Κάνω μαγικά (κολπα/ξόρκια. Depends on context) etc. You don't have to learn it as a rule though. It's not vital. You can always say Διαβάζω αστυνομικά βιβλία, Βλέπω αθλητικά νέα etc and be perfectly understood.^.^
Does anyone know why when sentence is negative we don't use article
There is no such rule in Greek, and I don't think there is one in English either. Magic is a general term here, so the article is omitted in both languages. ^.^