How do i make an addition table?

For a example i have an array that contains numbers. How do i make it in such a way that if i add values, the answer it will get will be from an element in the array. Just like in a multiplication table wherein for example i multiply 2x2, it will locate 4 in the array the only difference is that in the table that i want, i have values that i assign. Im making a galois field if you are asking what for.

Answer 1

[José-Luis]

 doc bsxfun