int x = 42; int y = x + 4; // y = 46, x is still 42 x = x + 4; // x is now 46; or I can write x += 4; --------------------------- int z = 11; int w = z += 2; ------------------------------- If I want to add/subtract a 1 from a field I can code: int r = 10; r = r + 1; r += 1; r++; // add 1 to r, and store in r Java support pre-increment and post-increment r++; // post "Use the field THEN add to it" ++r; // pre "Add to the field, then use it"