example
99+ 1-35*2
= 99+ 1-70
= 100-70
= 30
operation sequence
Among the four operations, addition and subtraction are called primary operations, and multiplication and division are called secondary operations. Expressions that contain two or more operations are usually called mixed operations. The mixed operation of addition, subtraction, multiplication and division is also called elementary arithmetic. In elementary arithmetic, the prescribed calculation order is called operation order.
How to calculate offline
The main thing to master is to remember to calculate multiplication and division first, and then add and subtract. In the successive calculation of multiplication and division, it should be calculated from left to right. When you encounter parentheses, you must first calculate the inside of parentheses. In the process of separation, the operation sequence line should be drawn according to the operation sequence, and the "three checks" should be done well. First of all, check whether the numbers and symbols copied from books to exercise books are correct. Second, check whether the numbers and symbols copied from horizontal to vertical are copied correctly. Third, it is necessary to check whether the draft is copied vertically, horizontally, and whether the decimal point position is correct or not.
pay attention to
It must operate from left to right according to the principle of "multiply first, then divide, then add and subtract", and the numbers in parentheses, brackets and braces must be calculated first, so various algorithms can be used to make its calculation simpler and more accurate. (Note: The formula may contain letters. )