数,在数学中占据重要地位,也是人类文明的重要组成部分.数学产生和发展的重要推动力之一,就是人们不断地深化对数的认识.虽然同学们已经学习了许多关于数的知识,但是这些仅仅是对于数的初步认识.进入中学以后,大家还要继续学习更多关于数的知识.数系是数的系统的简称,它包含了数的概念及其运算法则、规律等.同学们已学习过整数、分数、小数、正数、负数等概念和相关运 Number, occupy an important position in mathematics, but also an important part of human civilization.One of the important driving forces behind the development and production of mathematics is that people continue to deepen the understanding of the number.Although the students have learned a lot about the number of knowledge, But these are only a preliminary understanding of the number.After entering secondary school, we still need to continue to learn more about the number of knowledge.The number system is the number of short, it contains the number of concepts and algorithms, laws, etc. Students We have learned the concepts and related concepts of integers, fractions, decimals, positive numbers, and negative numbers