korean grammar: 에다/에다가

This ending can be seen as an extension of 에-ae. 에-ae is used to indicate a location, either one where you are now, or where you are going, or where you are putting something:

• 집에 있어요jip-ae iss-eo-yo ->Im at home
• 집에 가어요jip-ae ga-yo -> I'm going home
• 가방을 집에 두고 놓았어요ga-bang-eul jip-ae du-go no-ass-eo-yo ->I put my bag in the house

In the first example it indicates place, so there is no movement. In the second you are moving yourself to one place. But in third sentence you move something from one place to another. It's here that you can add 에다(가)-ae-da-ga to the 에-ae.

If you want to stress that you have transferred something from on place to another, rather than just put it somewhere different, you use -다(가)da-ga. So for third example you're kind of saying "the bag was outside, but I put it inside the house".

• 김치 냉장고에다 놓았어요kim-chi neng-jang-go-ae-da sd-ass-eo-yo ->I put the kimchi into the fridge
• 책을 책상 위에다가 놓았어요chek-eul chek-sang wi-ae-da-ga noa-ass-eo-yo ->I put the book on the top of the table
• 책에다가 번호를 적어 놓았어요chek-ae-da-ga beon-ho-reul jeok-eo no-ass-eo-yo ->I wrote the number down into the book

This ending really stresses there is a change of place to a new, clearly defined place. It's grammatical name is the "transferentative" and is also found on verbs, doing pretty much the same thing.