1, positive and negative numbers
Positive number is a mathematical term. Numbers greater than 0 are called positive numbers, and 0 itself is not a positive number. Negative number is a mathematical term. Numbers less than 0 are called negative numbers, and negative numbers and positive numbers represent quantities with opposite meanings.
2. Negative numbers
Negative numbers are mathematical terms, 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".
3. Positive numbers
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 "Nine Chapters Arithmetic" in China's ancient mathematical works.
4. What is 0?
0 is an integer between-1 and 1, which is the smallest natural number and also a 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.