1, digital sequence table, also known as digital value table or bit weight table, is a common tool in mathematics learning. It is used to represent the weight of each digit in a multi-digit number or the value represented by that digit. The basic principle of digital sequence table is to assign different bit weights according to the position of numbers.
2. Generation of numbers. In ancient times, people needed to "count" the number of objects and people. In production and labor, there is a need for counting gradually, and the methods of counting one by one, such as physical counting, knotting counting and lettering counting, are used.
With the increase of the number of people and the need of communication, the original counting method is becoming more and more impractical. Later, people invented some notation symbols called numbers.
3. Natural numbers, the generation of natural numbers is the need of human production and life. 1, 2, 3, 4 ..... All the objects are natural numbers, and there are no objects. Represented by 0, it is also a natural number. All natural numbers are integers. The smallest natural number is 0. There is no maximum natural number, and the number of natural numbers is infinite.
The first volume of fourth grade mathematics mainly involves integers and negative numbers, arithmetic operations, the popularization and application of fractions and numbers, and the nature and laws of numbers.
1, integers and negative numbers: the concepts and representations of positive and negative integers, the addition and subtraction of integers, and the representation and comparison of integers on the number axis.
2. Arithmetic operation: the operation rules of addition, subtraction, multiplication and division and the operation in complex situations (such as addition and multiplication of multiple numbers).
3. Fraction: the concept and expression of fraction, the addition and subtraction of fraction, and the conversion between fraction and integer.
4. Expansion and application of numbers: understanding and representation of four or five digits within ten, ranking and comparison of numbers, and application of numbers in real life (such as time, temperature, length, etc.). ).
5. The nature and laws of numbers: the concepts and judgments of even and odd numbers, the observation and discovery of multiples and divisors of numbers, and the laws of series and numbers.