Why introduce positive and negative numbers? Please give an example

Please adopt o (∩)_ ∩)O

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11. Why are positive and negative numbers introduced
12. Why is a positive divided by a negative equal to a negative
13. Does the concept of remainder exist in negative numbers? How to divide a positive number by a negative number?
14. If the rational number of a divided by a equals - 1, then a is: A, positive number B, negative number C, non negative number d, non positive number
15. Negative divided by negative equals negative multiplied by what What's more, a positive number divided by a negative number equals a positive number multiplied by what? Then 1 / 3 divided by (- 4 / 3) = 1 / 3 * (?)
16. What is a negative number divided by a negative number
17. What is a negative number divided by a negative number
18. The result and remainder of dividing a negative number by an integer For example, what is the result of - 9 divided by 4, and what is the remainder?
19. How to calculate the remainder by dividing a negative number by a positive number? This kind of problem how to calculate, such as - 3 divided by 5 have remainder? How to calculate? Can quotient be negative? For example, if I say - 3 divided by 5, quotient - 1, remainder 2, I hope someone who really understands can teach me My original question is to write the set of numbers divided by 3 and 2, that is, the set of numbers divided by 3 and 2. I don't know whether negative numbers can be included, because I can write negative numbers in my answers, but I have some doubts. After all, the answers are sometimes wrong,
20. The remainder of a negative number divided by a positive number -17 or - 7 divided by 4 -17 △ 4 = - 5, isn't it?