in mathematics, the character " * " symbolizes multiplication (x). thus;
2+2x2 = 8 considering the first equation (addition) is operated, then the multiplication follows = (2+2)x2
2+2x2 = 6 considering the last equation (multiplication) is operated = 2+(2x2).
between these two facts, in absence of the parenthesis (), the former equation is always considered (i.e. product = 8).