Follow the order of operations or PEMDAS. P for parentheses, E for exponents, M and D for multiplication and division (do these left to right and NOT all multiplication before division), then A and S are for addition and subtraction... Also do these left to right. So
35 + 20/5 - 4Ă—7 =
35 + 4 - 28 =
39 - 28 =
11