1. In mathematics, negative numbers are numbers less than 0, and negative numbers and positive numbers represent quantities with opposite meanings.

2. In life, we often encounter various quantities with opposite meanings. For example, there are surpluses and deficits in accounting; When calculating the rice stored in the granary, sometimes you should remember the grain and sometimes you should remember the valley. For convenience, people introduced the concepts of positive and negative numbers, recording the remaining money as positive numbers and the lost money as negative numbers. It can be seen that both positive and negative numbers are produced in production practice. ?

Negative numbers can be widely used in temperature, floor, altitude, water level, profit, increase or decrease of output, expenditure/income, score/deduction, etc. Common negative numbers in life are:

1. Turpan basin in Xinjiang is below sea level 155m, and the height should be expressed as (-155m)?

2. The 25 freshmen transferred from the fourth grade of the school are recorded as (+25), and the 18 transferred from the fifth grade should be recorded as (-18)?

3. Write "doing right 1, plus 5 points" as "+5" and "doing wrong 1, minus 5 points" as (-5)?

4. Today, the stock rose from 10 to1,which is+1 yuan. Then tomorrow 1 1 yuan will fall to 10.5 yuan, which means (-0.5) yuan.

The lowest temperature on the earth's surface is -88.3℃ at the South Pole.

6. The temperature of water is positive above 0, and the temperature of ice is negative below 0.

7. My family lives on the 1 floor, and there is an underground parking lot downstairs, which can be called the (-1) floor.

8. I earned 100 in business today, which means (+100), but I accidentally got it stolen when I went home, which means (-200).

Extended data

The introduction of negative numbers is a great contribution of China's ancient algebra to mathematics. In the eighth chapter "Equation" of the arithmetic classic "Nine Chapters Arithmetic" in ancient Qin and Han Dynasties, negative numbers were freely introduced. If there are negative numbers in the coefficients and constant terms of the equation, take "selling (making money)" as positive, "buying (paying money)" as negative and "remaining money" as positive, then "not enough money" as negative.

On the issue of grain calculation, the profit (grain increase) is positive and the loss (grain decrease) is negative. The book also points out: "The gains and losses of the two calculations are opposite and should be named after positive and negative." At that time, it was calculated, so in the calculation, the corresponding provisions of red chips are positive and black chips are negative; Otherwise the calculation will be straight and negative. In this way, positive and negative numbers can be clearly distinguished when encountering quantities with opposite meanings.

References:

Baidu encyclopedia-negative number