What are positive numbers and negative numbers

What are positive numbers and negative numbers

Positive number:
If a number x > 0, it is said to be a positive number. A positive number can be preceded by a plus sign "+", but when there is no number in front of it, the plus sign is usually omitted. There are countless positive numbers, including positive integers and positive fractions
Negative number:
Less than zero（

0 is the ()

0 is the boundary between positive and negative numbers

Examples are given to illustrate the functions of positive and negative numbers in expressing quantities with opposite meanings

When distance is used as a vector operation, the positive and negative directions are opposite
In physics, when the computing power is large, positive and negative also indicate two opposite directions
In fact, many of them are too lazy to list one by one

Why negative numbers are introduced? Give examples to illustrate the functions of positive and negative numbers in expressing opposite quantities

Natural numbers and integers can't meet the needs of real life calculation, so we need to introduce the concept of negative numbers,
For example, 20 ° C above zero can be expressed as + 20 ° C, and 20 ° below zero can be expressed as - 20 ° C