The concepts of positive numbers and negative numbers are a mathematical term, and negative numbers and positive numbers represent quantities with opposite meanings. Negative numbers are marked with a negative sign "-"and a positive number, for example? 2 stands for the antonym of 2. Therefore, any positive number preceded by a negative sign becomes a negative number. A negative number is the reciprocal of its absolute value. On the number axis, negative numbers are all on the left of 0, and the earliest record of negative numbers is China's ancient mathematical work "Nine Chapters Arithmetic". In the calculation, it is stipulated that "positive calculation is red and negative calculation is black", that is, red calculation is used to represent positive numbers and black is used to represent negative numbers. Comparing the sizes of two negative numbers, the absolute value is larger but smaller.
Positive number is a mathematical term. Numbers greater than 0 are called positive numbers, and 0 itself is not a positive number. Positive numbers and negative numbers represent quantities with opposite meanings. Positive numbers are usually preceded by a "+"symbol, which can usually be omitted. Negative numbers are marked with a negative sign "-"and a positive number, for example? 2 stands for the antonym of 2. On the number axis, positive numbers are all on the right side of 0, and the earliest record of positive numbers is China's ancient mathematical work "Nine Chapters Arithmetic". In the calculation, it is stipulated that "positive calculation is red and negative calculation is black", that is, red calculation is used to represent positive numbers and black is used to represent negative numbers. Comparing the sizes of two negative numbers, the absolute value is larger but smaller.
What is 0? 0 is an integer between-1 and 1, the smallest natural number and the rational number. 0 is neither positive nor negative, but the dividing point between positive and negative numbers. 0 has no reciprocal, the reciprocal of 0 is 0, the absolute value of 0 is 0, the square of 0 is 0, the square root of 0 is 0, the cube root of 0 is also 0, 0 times any number equals 0, and the power of 0 of any number except 0 equals 1. 0 cannot appear as denominator or divisor, all multiples of 0 are 0, and 0 divided by any non-zero real number equals 0.
China's primary and secondary school textbooks originally stipulated that natural number set does not include 0. But outside China, most mathematicians stipulate that 0 is a natural number. In order to facilitate international exchanges, national standards stipulate that natural number set includes 0. Therefore, in our newly published textbooks, according to "national standards", the set of natural numbers is called the set of positive integers in modern times. At the same time, we also use some mathematical symbols according to the national standards.
From the point of view of use, it doesn't matter much whether the set of natural numbers contains 0. As ordinal number, starting from 0 is the same as starting from 1; We used to say n∈N, now we just need to say that n is a positive integer (n∈N+).