In elementary mathematics, when the first-level operation plus sign and the second-level operation multiplication and division appear in the same formula at the same time, their operation order is multiplication and division first, then addition and subtraction. If there are parentheses, count the parentheses first and then the parentheses, and the operation order at the same level is from left to right.
Such operations are called four operations, and four refers to the calculation rules of addition, subtraction, multiplication and division. The formula of four operations does not necessarily have four operation symbols, but generally refers to the operation in which two or more operation symbols and brackets combine most of them into a number.
Addition: the operation of combining two numbers into one number, the operation of combining two decimals into one decimal, and the operation of combining two fractions into one fraction.
Subtraction: The operation of finding the other addend by knowing the sum of two addends and one of them.
Multiplication: A simple operation to find the sum of several identical addends. The meaning of decimal multiplication by integer is the same as that of integer multiplication. Multiplying a number by a pure decimal is to find a few tenths and a few percent of this number.
Division: knowing the product of two factors and one of them, the operation of finding the other factor has the same meaning as integer division.
The significance of four operations
The meaning of 1 and the four operations is to combine multiple numbers to calculate.
The operation of combining two numbers into one number is called addition. As we all know, the sum of two addends, one of which seeks the other addend, is called subtraction.
3. The simple operation of finding the sum of several identical addends is called multiplication. Given the product of two factors and one of them, the operation of finding the other factor is called division.