Assigment Question

Question

Will Some Other Primitive Operator(Like +,*,-)Affect The Assignment Operator?,The Example Code

num1=8;
num2=2;
num2 -= num1 + num2;

Will The Output Is Still 8?,Or Produce An Error?(Cause I Want To Solve One Of The Code Project)

Answer 1

num2 -= num1 + num2 subtracts from num2 the sum of num1 and num2

Answer 2

What Was The Reason It Becomes -8?