Noob trying to understand defence

[Immali]

Hello, i'm learning the game and have a question i cannot answer.
If i build a a Rampard it says it has a defence value of 100. Then, in the province part of the screen there's defence+/-.
Does this mean that if i build the rampard the defence goes to 100 and then i put 10 points and it goes to 110??

Thanks a lot for any help