Can anyone explain this to me

Question

int x = 1
int y = 2
string s = "+x+y+(x+y);
system.out.println(s);

Answer 1

123

() first and from left to right with type casting

s = "" + 1 + 2 + (1+2)
s = "" + 1 + 2 + 3
s = "1" + 2 + 3
s = "12" + 3
s = "123"