Why the output of second sqr(3+1) is 7?

Question

#define sqr(i) i*i
int main()
{ printf("%d %d ",sqr(3),sqr(3+1));
}

Answer 1

Note sqr() is i*i, not (i)*(i)
sqr(3) -> 3*3
sqr(3+1) -> 3+1*3+1 -> 3+3+1 -> 7

Answer 2

Thank you👍