The percentage of knowledge (1) indicates that one number is the percentage of another. Percent is also called percentage or percentage. Percentages are usually not written in the form of fractions, but are represented by the symbol "%"(called percent sign). If it is written as 4 1%, 1% will do. Because the denominator of the percentage is 65438+. Percentage is widely used in industrial and agricultural production, science and technology and various experiments. Percentages are often used for investigation, statistics, analysis and comparison. (2) The formation of the concept of percentage should be introduced with examples from students' real life or industrial and agricultural production. For example, there are 100 students in senior one, among whom 47 are girls, accounting for 47% of the whole grade. There are 200 senior two students, including girls 100, accounting for 50% of the whole grade (). In these two examples, the number of students in both grades is "standard quantity" and the number of girls is "comparative quantity". In the teaching of percentage application problems, we should grasp the quantitative relationship of = percentage (percentage) for analysis.
On a hot summer day, I was in a hurry to run home from school, always thinking about the big watermelon in the refrigerator at home. As soon as I got home, I threw my schoolbag aside and hurriedly opened the refrigerator. As soon as I opened the refrigerator, my father smiled and said, "If you want to eat watermelon, you have to go through me first." I just want to eat watermelon in my heart. Without considering the exam, I said loudly, "Oh, come on, I won't be afraid of you." Dad worried for a while and said, "The total output value of a factory is 6.5438+0.8 million yuan, an increase of 20% over last year. What was the total output value of this factory last year? Just tell me the number formula and you can eat watermelon. " I said, "Oh, you despise me for such a simple question! Dad said, "Stop nagging here and tell me the formula." I blurted out: "The numerical formula is 1800 divided by 1 minus 20% to get the answer. Haha, I am awesome! "! Dad smiled and said, "Ha ha, I was wrong. You clearly see that you already know the whole one, whether it is division or multiplication. " I thought for a moment and said with shame, "The formula is 1800 times 1 minus 20% to get the answer. Well, I sighed. How could I get such a simple question wrong? I really shouldn't! Dad said; "Don't lose heart, son, just change it later." Dad cut the big watermelon into pieces. When we were eating, Dad said, "Ah, this watermelon is so sweet!" " "But I think watermelon is not sweet, but a very painful and sad feeling.
I believe that everyone has encountered some things related to percentage in their lives. Let's write it! I am waiting for you.