小数作为分数

[Figure 1]

About 0.71 of the surface of the Earth is covered with water. That means 0.29 of the Earth's surface is land. What fraction of the surface of the Earth is water? What fraction of the Earth's surface is land?
::地球表面约有0.71个水覆盖着地球表面。这意味着地球表面0.29个是陆地。地球表面的哪一部分是水?地球表面的哪一部分是陆地?

In this concept, you will learn to convert decimals to fractions.
::在此概念中, 您将学习将小数点转换为分数 。

Converting Decimals to Fractions
::将十进制转换成分数

Decimals and fractions are related. They both represent a part of a whole. With a decimal, the part of a whole is written using a  decimal point . With a fraction, the part of a whole is written using a fraction bar and has a  numerator  and a  denominator . Because fractions and decimals are related, decimals can be written as fractions. Use the  place value  of the decimal to convert it to a fraction.
::十进制和分数是相关联的。它们都代表整体的一部分。如果小数点为小数点,则以小数点为小数点写入整个部分。如果分数点为小数点,则以分数栏和分母写入整个部分。由于分数和小数点是相关联的,小数点可以作为分数写入。使用小数点的位置值将其转换成分数。

Here is a decimal number.
::这是十进制数字。

0.67

The chart represents the  place value  of the decimal number.
::图表显示小数点数的位置值。

The fraction is described by reading the decimal, “sixty-seven hundredths.” The numerator is 67 and the denominator is 100. The place value of the decimal number will indicate the denominator of the fraction.
::分数通过读读小数“六千七百 ” 来描述。 分子为67,分母为100。 小数数的位数值将表示分数的分母。

$\begin{array}{r}0.67=\frac{67}{100}\end{array}$

Here is another decimal number
::这里是另一个小数位数

0.5

Convert this decimal number to a fraction.
::将此小数数转换为分数 。

This decimal number is read as “five tenths.” The numerator is the five and the denominator is the place value of tenths.
::这个小数位数被读作“十进制 ” 。 分子是五,分母是十进制的位值。

$\begin{array}{r}0.5=\frac{5}{10}\end{array}$

You can  simplify  the fraction. The   (GCF) of 5 and 10 is 5.
::您可以简化分数。 5和10的(GCF)是5。

$\begin{array}{r}\frac{5}{10}=\frac{1}{2}\end{array}$

0.5 is written as  $\begin{array}{r}\frac{5}{10}\end{array}$  or  $\begin{array}{r}\frac{1}{2}\end{array}$ .
::0.5以5 10或12写成。

Examples
::实例

Example 1
::例1

Earlier, you were given a problem about the Earth’s water and land.
::更早之前,你们曾遇到地球的水和土地问题。

About 0.71 of the entire Earth is water and 0.29 of the Earth is land. Convert the decimals to fractions to find the fraction of the Earth that is water and land.
::整个地球约有0.71个是水,0.29个是土地。将小数转换成小数,以找到地球的水和土地部分。

First, convert the decimal 0.71 to a fraction. 0.71 is 71 hundredths.
::首先,将小数点 0.71 转换为分数。 0.71 是 7100 。

$\begin{array}{r}0.71=\frac{71}{100}\end{array}$

71 is a  prime  number and cannot be simplified.
::71是质数,无法简化。

Then, convert the decimal 0.29 to a fraction. 0.29 is 29 hundredths.
::然后,将小数点0.29转换为分数。 0.29是2900。

$\begin{array}{r}0.29=\frac{29}{100}\end{array}$

29 is also a prime number and cannot be simplified.
::29也是一个质数,无法简化。

The Earth is  $\begin{array}{r}\frac{71}{100}\end{array}$  water and  $\begin{array}{r}\frac{29}{100}\end{array}$  land.
::地球是71 100个水和29 100个土地。

Example 2
::例2

Jessie has completed 0.85 of her homework. If she was going to express this number as a fraction what would the fraction be? Write your answer in  simplest form .
::Jessie已经完成了0.85个家庭作业。如果她要将这个数字作为一小部分来表达,那分数会是什么?用最简单的形式写下你的答复。

First, convert the decimal number to a fraction. 0.85 is eighty-five hundredths. The numerator is 85 and the denominator is 100.
::首先,将小数数转换成一个分数。 0. 85是八千五百。 分子为85, 分母为100。

$\begin{array}{r}\frac{85}{100}\end{array}$

Then, simplify thefraction. The greatest common factor of 85 and 100 is 5.
::然后,简化违规情况,85和100的最大共同系数是5。

$\begin{array}{r}\frac{85}{100}=\frac{17}{20}\end{array}$

0.85 is written as  $\begin{array}{r}\frac{17}{20}\end{array}$ .
::0.85的写法是17 20。

Example 3
::例3

Convert the decimal number to a fraction in simplest form.
::以最简单的形式将小数数转换为分数。

0.8

First, convert the decimal to a fraction. 0.8 is 8 tenths.
::首先,将小数点转换为小数点。0.8是8十分。

$\begin{array}{r}0.8=\frac{8}{10}\end{array}$

Then, simplify the fraction. The GCF of 8 and 10 is 2.
::然后简化分数,全球合作框架8和10是2。

$\begin{array}{r}\frac{8}{10}=\frac{4}{5}\end{array}$

0.8 is written as  $\begin{array}{r}\frac{4}{5}\end{array}$  in simplest form.
::0.8以最简单的形式写成4 5。

Example 4
::例4

Convert the decimal number to a fraction in simplest form.
::以最简单的形式将小数数转换为分数。

0.25

First, convert the decimal to a fraction. 0.25 is 25 hundredths.
::首先,将小数点转换为分数。0.25是2500。

$\begin{array}{r}0.25=\frac{25}{100}\end{array}$

Then, simplify the fraction. The GCF of 25 and 100 is 25.
::然后简化分数,全球合作框架25和100是25。

$\begin{array}{r}\frac{25}{100}=\frac{1}{4}\end{array}$

0.25 is written as  $\begin{array}{r}\frac{1}{4}\end{array}$  in simplest form.
::0.25以最简单的形式写成14。

Example 5
::例5

Convert the decimal number to a fraction in simplest form.
::以最简单的形式将小数数转换为分数。

0.75

First, convert the decimal to a fraction. 0.75 is 75 hundredths.
::首先,将小数点转换为分数。 0.75是7500。

$\begin{array}{r}0.75=\frac{75}{100}\end{array}$

Then, simplify the fraction. The GCF of 75 and 100 is 25.
::然后简化分数,全球合作框架75和100是25。

$\begin{array}{r}\frac{75}{100}=\frac{3}{4}\end{array}$

0.75 is written as  $\begin{array}{r}\frac{3}{4}\end{array}$  in simplest form.
::0.75以最简单的形式写成3 4。

Review
::回顾

Write each decimal as a fraction. Do not simplify.
::将小数点中的每个小数点写成一个分数。 不要简化 。

1. 0.67
2. 0.33
3. 0.45
4. 0.27
5. 0.56
6. 0.7
7. 0.98
8. 0.32
9. 0.04
10. 0.07
11. 0.056
12. 0.897
13. 0.372
14. 0.652
15. 0.032

Review (Answers) 
::回顾(答复)

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 。

Resources
::资源