Language / here / there - difference rules in Polish [7]

I'm a little confused. Is "Tu są cztery krzesła" and "To są trzy jabłka" the same as saying "Here are four chairs" and "They are three apples"?

Language / Beginner learner of Polish having trouble with nouns - they change as well as numbers? [27]

When asking how many things there are, is the genitive case always used?

For example: "Ile jest jabłek?", "To są trzy jabłka" (for three) or "To jest sześć jabłek" (for six)

Language / Beginner learner of Polish having trouble with nouns - they change as well as numbers? [27]

Thanks, I didn't spot that mistake, but the question still remains, is the genitive case always used when asking how many there are?

Ile to jest jabłek (gen.)