You don’t necessarily have to do parentheses first. What matters is that the things inside the parentheses are a group that you can’t break apart. If you have 10÷2+3-2*(2+1) you can do the division first 5+3-2*(2+1) then the addition outside the parentheses 8-2*(2+1) It’s just that before you do the multiplication of the term outside the parentheses, you have to handle the parentheses group, so you get 8-2*3 -> 8-6 -> 2
You don’t necessarily have to do parentheses first. What matters is that the things inside the parentheses are a group that you can’t break apart. If you have
10÷2+3-2*(2+1)you can do the division first5+3-2*(2+1)then the addition outside the parentheses8-2*(2+1)It’s just that before you do the multiplication of the term outside the parentheses, you have to handle the parentheses group, so you get8-2*3->8-6->2