6.1百分点

Section outline

• Select section General

  Collapse Expand

  General

  Collapse all Expand all

  • Select activity 新闻通告

    

    新闻通告 Forum
• Select section 百分点

  Collapse Expand

  百分点

  

  [Figure 1]

  播放段落

  Randy looked at his smartphone and saw that he had only 15% of his battery power remaining. That got him wondering, ‘What does 15% mean?’ How much of the phone’s total battery power does Randy have left?
  ::兰迪看着他的智能手机,发现他只有15%的电池电力剩余。 这使他想知道,“15%是什么意思? ”兰迪的手机总电池发电量还剩下多少?

  播放段落

  In this concept, you will learn to recognize percent as a ratio whose  denominator  is 100.
  ::在这个概念中,你将学会承认百分率是分母为100的比例。

  播放段落

  Recognizing Percents
  ::承认百分比

  播放段落

  Percent  means the number of parts  per  100. You know that 100% of anything is the entire or whole  amount . Therefore, percents can tell you what part of the whole you are dealing with. To understand percents, you will set up ratios.
  ::百分率是指每100个部件的数量。你知道,任何东西的100%是整数或整数。因此,百分率可以告诉你整体中你所处理的是哪个部分。为了理解百分比,你将建立比率。

  播放段落

  A  ratio  is a comparison of two numbers and that a ratio can be written in three ways. For example: 1 to 2, 1:2, or  $\begin{array}{r}\frac{1}{2}\end{array}$ . Percents are ratios in which the second number (or the denominator) is 100.
  ::一个比率是两个数字的比较,一个比率可以用三种方式写成。例如:1至2、1:2或12。百分比是第二个数字(或分母)为100的比率。

  播放段落

  Let’s look at an example.
  ::让我们举个例子。

  播放段落

  If there are 13 red jelly beans and 15 yellow jelly beans in a jar, the ratio of red jelly beans to yellow jelly beans can be written as 13 to 15, 13:15, or  $\begin{array}{r}\frac{13}{15}\end{array}$ . Each of these ratios is read as “thirteen to fifteen.”
  ::如果罐子里有13个红果豆和15个黄果豆,那么红果豆与黄果豆的比例可以写为13至15、15至15或13至15。

  

  [Figure 2]

  播放段落

  A percent is a type of ratio. You are now going to apply percents directly to ratios.
  ::A% 是一种比例类型。 您现在将直接应用百分比对比例 。

  播放段落

  A percent is a ratio that compares a number to 100. Percent means “per hundred” and the symbol for percent is %.
  ::A%是将数字与100之比的比率, 百分率是指“百分率”, 百分率的符号是%。

  播放段落

  100% represents the ratio 100 to 100 or  $\begin{array}{r}\frac{100}{100}\end{array}$ . Therefore, the value of 100% is 1.
  ::100%代表100比100或100比100。因此,100%值为1。

  播放段落

  Let’s look at another example.
  ::让我们再看看另一个例子。

  播放段落

  If there are 100 jelly beans in a jar and 19 are black, you can say that  $\begin{array}{r}\frac{19}{100}\end{array}$ or 19% of the jelly beans in the jar are black.
  ::如果罐子里有100个果冻豆,19个是黑色, 你可以说罐里19个100%或19%的果冻豆是黑色。

  播放段落

  Let’s look at one more situation that uses a real-life scenario.
  ::让我们再看看一个使用现实生活情景的情况。

  播放段落

  There were 100 questions on a test and Amanda answered 92 of them correctly. What percent did she answer correctly? What percent did she answer incorrectly?
  ::测试中有100个问题,阿曼达正确回答了其中92个问题。她正确回答的比例是多少?她错误回答的比例是多少?

  播放段落

  Amanda answered 92 out of 100 questions correctly. First, you can write this as the ratio  $\begin{array}{r}\frac{92}{100}\end{array}$ .
  ::阿曼达正确回答了100个问题中的92个。 首先,你可以把它写成92100的比例。

  播放段落

  Next, since the denominator is 100, you can write this ratio in percent form as 92%.
  ::接下来,既然分母是100, 你可以以92%的百分率写出这个比例。

  播放段落

  Then, since there were 100 questions on the test and Amanda answered 92 correctly, you can determine that she answered  $\begin{array}{r}100-92\end{array}$ , or 8 out of 100 incorrectly.
  ::阿曼达正确回答92, 你可以确定她回答100 - 92, 或者说100人中有8人答错了。

  播放段落

  Next, you can write this as the ratio  $\begin{array}{r}\frac{8}{100}\end{array}$ and as the percent 8%.
  ::接下来,你可以把它写成8100比,8%比。

  播放段落

  The answer is Amanda answered 92% of the questions correctly and 8% incorrectly.
  ::答案是阿曼达正确回答了92%的问题 错误回答了8%的问题

  播放段落

  Examples
  ::实例

  播放段落

  Example 1
  ::例1

  播放段落

  Earlier, you were given a problem about Randy and his smartphone battery indicator.
  ::之前,你得到一个问题 关于兰迪和他的智能手机 电池指示器。

  播放段落

  It showed that he had 15% of his battery power remaining. How could you write this percent as a fraction?
  ::它显示他有15%的电池剩余电力。你怎么能将这个百分比作为一个分数来写呢?

  播放段落

  First, you can write this as the ratio 15:100, which is equivalent to  $\begin{array}{r}\frac{15}{100}\end{array}$ .
  ::首先,您可以写为15:100的比例,相当于15:100。

  播放段落

  Then, since the denominator is 100, you can write this ratio in percent form as 15%.
  ::那么,既然分母是100, 你可以以15%的百分率来写这个比例。

  播放段落

  The answer is 15% is equivalent to the fraction  $\begin{array}{r}\frac{15}{100}\end{array}$ .
  ::答案是15% 等于分数15100

  播放段落

  Example 2
  ::例2

  播放段落

  Write a ratio and a percent that describes the shaded part of the square.
  ::写出比例和百分比 描述方形的阴影部分。

  

  [Figure 3]

  播放段落

  First, count the number of shaded squares and the number of total squares. The figure shows the ratio of 37 shaded squares to 100 squares.
  ::首先,计算阴影方形的数目和总平方形的数目。图中显示37阴影方形对100平方形的比率。

  播放段落

  Next, write this ratio as 37 to 100, 37:100, or  $\begin{array}{r}\frac{37}{100}\end{array}$ .
  ::接下来,写这个比例是37比100,37比100,37比100,或37比100。

  播放段落

  Then, when the denominator of a ratio in fraction form is 100, you can express the ratio as a percent.
  ::然后,当比例分数的分母分母为100时,你可以以百分比表示该比例。

  $$\begin{array}{r}\frac{37}{100}=37\mathrm{\%}\end{array}$$

  播放段落

  The answer is: the ratio that describes the shaded part is 37 to 100, 37:100, or
  ::答案是:描述阴影部分的比率是37比100,37比100,或

  播放段落

  $\begin{array}{r}\frac{37}{100}\end{array}$ , and the percent is 37%.
  ::37 100%, 37%。

  播放段落

  This is a visual way of showing a percent as a ratio. You can use the picture to write the ratio and the percent.
  ::这是显示百分比比例的直观方式。 您可以用图片来写比例和百分比 。

  播放段落

  Example 3
  ::例3

  播放段落

  Solve the following problem. Karen ate 12 out of 100 blueberries. What percent of the blueberries did she eat?
  ::凯伦吃了100个蓝莓中的12个 她吃了多少蓝莓?

  播放段落

  First, you can write this as the ratio  $\begin{array}{r}\frac{12}{100}\end{array}$ .
  ::首先,你可以把它写成比例12100。

  播放段落

  Then, since the denominator is 100, you can write this ratio in percent form as 12%.
  ::那么,既然分母是100, 你可以写这个比例的百分之十二。

  播放段落

  The answer is she ate 12% of the blueberries.
  ::答案是她吃了12%的蓝莓

  播放段落

  Example 4
  ::例4

  播放段落

  Solve the following problem. Joey answered 93 questions correctly out of 100 questions on his test. What percent of the questions did he answer correctly and what percent did he answer incorrectly?
  ::解决下面的问题。 Joey在测试的100个问题中正确回答了93个问题。 他回答的占问题的比例是多少,错误回答的占多少?

  播放段落

  First, you can write this as the ratio  $\begin{array}{r}\frac{93}{100}\end{array}$ .
  ::首先,你可以把它写成93100的比例。

  播放段落

  Next, since the denominator is 100, you can write this ratio in percent form as 93%.
  ::接下来,既然分母是100, 你可以以百分比形式写成93%。

  播放段落

  Then, since there were 100 questions on the test and Joey answered 93 correctly, you can determine that he answered  $\begin{array}{r}100-93\end{array}$ , or 7 out of 100 incorrectly.
  ::然后,既然有100个问题 在测试和乔伊回答正确93, 你可以确定他回答100 - 93, 或100个中7个是错误的。

  播放段落

  Next, you can write this as the ratio  $\begin{array}{r}\frac{7}{100}\end{array}$ and as the percent 7%.
  ::接下来,你可以把它写成7100比7%。

  播放段落

  The answer is Joey answered 93% of the questions correctly and 7% incorrectly.
  ::回答是乔伊正确回答了93%的问题 7%回答错误

  播放段落

  Example 5
  ::例5

  播放段落

  Solve the following problem. Sarah gathered 25 roses out of 100 flowers. What percent of the flowers were roses?
  ::莎拉从100朵花中收集了25朵玫瑰。

  播放段落

  First, you can write this as the ratio  $\begin{array}{r}\frac{25}{100}\end{array}$ .
  ::首先,你可以把它写成25100的比例。

  播放段落

  Then, since the denominator is 100, you can write this ratio in percent form as 25%.
  ::那么,既然分母是100, 你可以以25%的百分率写出这个比例。

  播放段落

  The answer is 25% of the flowers were roses.
  ::答案是25%的花是玫瑰

  播放段落

  Review
  ::回顾

  播放段落

  Write each percent as a ratio with a denominator of 100.
  ::每一百分比按百分位数100的比例写。

  1. 10%
  2. 6%
  3. 22%
  4. 41%
  5. 33%
  6. 70%
  7. 77%
  8. 19%
  9. 25%
  10. 15%
  11. 7%
  12. 29%
  13. 88%
  14. 92%
  15. 90%

  播放段落

  Review (Answers)
  ::回顾(答复)

  播放段落

  Click   to see the answer key or go to the Table of Contents and click on the Answer Key under the 'Other Versions' option.
  ::单击可查看答题键, 或转到目录中, 单击“ 其他版本” 选项下的答题键 。

  播放段落

  Resources
  ::资源