(2) Decimal multiplication: first calculate the product according to the law of integer multiplication, and then look at how many decimal places there are in a factor * * *, counting the decimal points from the right side of the product. There is a 0 at the end of the product to simplify it.
(3) Decimal divided by integer: where the quotient is written except where it goes. The decimal point of quotient is aligned with the decimal point of dividend. If the integer part of the quotient is not enough 1, write 0 in each position. If there is a remainder at the end of the dividend, add 0 to continue the division.
Divide decimals by decimals, first change the divisor into integers, move the decimal point of the divisor to the right by several digits, then move the decimal point of the dividend to the right by the same number of digits, and divide it by decimals where the divisor is an integer.
A decimal with a finite number of digits after the decimal part. For example, 3. 1465, 0.364, 8.32 18798456, etc. All finite decimals belong to rational numbers and can be converted into component numbers.
A simplest fraction can be converted into a decimal finite fraction if and only if its denominator contains only prime factors 2 or 5 or both. Similarly, a simplest fraction can be transformed into a finite fraction of the base of a positive integer if and only if the prime factor of its denominator is a subset of the prime factor of the base.
Extended data:
When subtraction is used, the minus sign "?" Between two projects. The result is represented by an equal sign. For example, in other cases, subtraction is "understandable", even if no symbols appear:
For a column containing two numbers, the smaller number is displayed in red, which usually means subtracting the smaller number in the column. The difference between and below is under one line. This is very common in accounting.
Formally, the reduced number is called subtraction, and the reduced number is reduced.
According to mathematical rules, the process of replacing or transforming a quantity (or number) to get the expression result. It is the main content of mathematics research, and mathematics is the subject of studying quantity and its operation, graph and its transformation.
The most basic operation of numbers is four operations [arithmetic operation], that is, four operations of addition, subtraction, multiplication and division. Multiplying a number by several times is called power operation; When a number is raised to the power of n (n is a positive integer), it is called root operation. These four operations, together with power and root operations, are collectively called algebraic operations.
In advanced mathematics, besides algebraic operation, there are limit operation, derivative operation, integral operation and so on. The most basic operation is limit operation, and the operation related to limit is called "analytical operation".
Each operation has its own suitable algorithm, such as associative law, commutative law, distributive law and so on.
The original meaning of operation in Chinese is to carry a computing chip or stir a computing bead, and now it refers to any transformation in mathematics.
References:
Baidu encyclopedia-decimal