You can if you wrote everything as just addition and subtraction, but then we made some shorthand notations for that, such as 2x3=2+2+2, and so now you have to do multiplication before addition otherwise you get a wrong answer, and if you wrote all multiplications before all additions there’d still be no problem, but as someone else pointed are, there are cases where it’s easier to have a different order, and so voila! Order of operations rules.