How do I calculate GF(2) (Galois Field) without using a tool?

Question

I am stuck and can't find anything on Google or SO. I have:

1+1+1+0 and I am asked to calculate the answer over GF(2).

My question: what answer?

I have no clue what to do. Can someone help me by telling me what I should do? Where do I start? Making an addition table? I honestly have no idea what they are asking or what is being expected.

Answer 1

To answer my own question:

1+1+1+0 is the same as doing: ((1+1)+1) + 0 =

(1+1) = 0

(0) + 1 = 1

1 + 0 = 1

That gives me 1 as my answer.