You would use PEMDAS (Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction). This means you would use multiplication first because it is before addition or subtraction. That means you would do 4*9 = 36. So now you have 36 + 6 - 3. Since the next step is adding, add 6 to 36, and you will get 42. Then subtract 3 from 42 to get your final answer of 39. Hope this helps. Let me know if you don't understand something, and feel free to ask more questions.