Case issues

[lynxypoo.livejournal.com]

Does anyone know where I might find something to practice recognizing differences in the nomnative, prepositional, and accusative case? (I'll be learning the instrumental case in the next chapter).

behind the cut are a coulple excerpts from my latest excercise, what I thought it was, and what it should be- I just ask why?

2) Here is a blackboard, and there is a map.
Вот доску, а вот карту

Вот доскa, а вот картa.
>>Why are blackboard and map not accusative?

9) Where is Anne, at home or in school?
Где Анна, дому или школе?

>>Где Анна, домa или в школе?
Is дома irregular or for some reason -not- feminine? in the vocab it lists дома as 'at home', but most words ending in -a are feminine, and thus, change to y, right?


спасибо!