[Edit this paragraph] Application
The meaning of percentage and fraction
Percentages and scores are not exactly the same. Fraction can mean the fraction of a number in unit one, or it can mean a quantity, such as 1 meter half; But percentage can only indicate how much a number accounts for a unit, not a number.
Significance of percentage
Fraction refers to the fraction that one number is another number, which is called percentage. Percentages are called percentages or percentages. Usually, it is not written in the form of fractions, but expressed by adding a percent sign "%"after the original molecule. For example: 64/ 100 64% is used for writing and 64% for reading.
Although the denominator of the percentage is 100, the numerator can be greater than 100, for example, 200% means twice the original number. For example, a company's net profit last year was 6.5438+0.2 million yuan, and this year's net profit was 6.5438+0.2 million yuan, which can be expressed as "this year's net profit increased by 20% compared with last year" or "this year's net profit increased by 654.38+0.20% compared with last year", but this writing method is rarely used. Percentages are sometimes misleading. Many people think that an increase in percentage will be offset by a decrease in the same percentage. For example, a 50% increase in 100 equals 100+50, that is, 150. And a 50% reduction from 150 is 150-75, which is equal to 75. The final result is less than the original number 100.
Percentage in daily life
The weather forecast program on TV will broadcast the weather situation and precipitation probability of that night and tomorrow day every day, prompting everyone to prepare in advance, just like the precipitation probability of tonight is 20%, and there will be a strong wind of 5 ~ 6 in the daytime tomorrow, and the precipitation probability is 10%, so you should add clothes sooner or later. 20% and 10% are clear and concise.
With the rapid development of science and technology, every middle-aged person is now equipped with various styles of mobile phones. Glenn Wilson, a psychologist at Royal College, University of London, has proved that reading short messages with his head down all the time will lead to low work efficiency and slow down the brain reaction ability of staff, and the IQ of people who read short messages often will drop by 10%, which once again proves in percentage form that although mobile phones provide convenience for people, they are very harmful to human health.
This is the information about percentage that I found in my life. I believe that as long as you observe carefully, you will also find that percentage is everywhere in your life.
80%
China is the largest producer of energy-saving lamps in the world, but 80% of its products are exported, and the domestic consumption is seriously low.
47. 1%
According to 200 1 undergraduate and junior college students, 47. 1% of the contracted college students have a monthly salary below 1500 yuan.
85.53%
According to an online survey, 85.53% of netizens have never read a famous book in recent years. In addition, 8.58% netizens have never read a famous book in the past ten years, and 6.75% netizens said that they have never read a famous book.
[Percentage of application problems]
1. Xiaoming reads a story book. The ratio of the number of pages read on the first day to the total number of pages is 3: 7. If he reads 15 page again, it is exactly half of this book. How many pages are there in this book?
2. Mathematics interest group * * *, with 42 students, 2/7 of whom are girls. Later, several girls were added. At this time, girls accounted for 2/5 of the total number. How many girls did you add?
3. Two baskets of apples * * * 90kg, big basket 1/5, small basket 1/4 * * 20kg. How many kilograms of fruit are there in the big basket and the small basket?
4. The ratio of the construction area of the Oriental teaching building to the playground area is 27: 100, and the ratio of the construction area of the movable building to the playground area is 19: 100.
(1) What percentage of the teaching building area is equivalent to the playground area? A: The teaching building covers an area equivalent to 27% of the playground area.
(2) What percentage of the playground area is occupied by the activity building? A: The construction area of the activity building is equivalent to 19% of the playground area.