第三单元

Unit three

Mathematics in Paper Cutting -- Addition and Subtraction of Fractions (I)

(剪纸中的数学——分数加减法（一）)

1. The paper is 24 centimeters long and 18 centimeters wide.

这张纸长24厘米，宽18厘米。

2. How many centimeters can the sides of a square be if there is no left over?

要想剪完后没有剩余，正方形的边长可以是几厘米呢？

3. How many centimeters is the longest?

最长是几厘米？

4. Use squares of paper of different lengths to swing them.

分别用不同边长的正方形纸片摆一摆。

5. You don't have to fiddle. You can do the math.

不用摆一摆，算一算也能知道。

6. The sides of a square can be 1cm, 2cm, 3cm, 6cm.

正方形的边长可以是1厘米、2厘米、3厘米、6厘米。

7. The longest is 6 centimeters.

最长是6厘米。

8. What does one, two, three, six have to do with 24, 18?

1、2、3、6与24、18有什么关系呢？

9. They were found to be factors of both 24 and 18.

发现它们既是24的因数，也是18的因数。

10. They're a common factor of 24 and 18.

6.is the largest, the greatest common factor of 24 and 18.

它们是24和18的公因数。其中6是最大的，是24和18的最大公因数。

7. How do you find the common factor and the greatest common factor of 12 and 18?

怎样找12和18的公因数和最大公因数？

8. Method 1: enumeration method method 2: screening method

方法一：列举法    方法二：筛选法    

9. You can also use short division to find the greatest common factor of 12 and 18.

还可以用短除法求12和18的最大公因数。

Lesson two

1. How much of the paper did the carp and the butterfly share?

剪鲤鱼和剪蝴蝶一共用了这张纸的几分之几？

2. The basic properties of fractions make it possible to convert a result into a simpler fraction.

根据分数的基本性质可以把得数化成更简单的分数。

3. What do you mean by a division?

什么叫作约分？

4. Would you divide the twelfth of the eighteenth?

你会把十八分之十二约分吗？

5. Why did they come out differently?

他们约分的结果为什么不同呢？

6. What is the simplest fraction?

什么叫做最简分数？

7. How can we write the approximate form?

约分可以写成什么形式？

8. How many parts of this piece of paper does it take to cut a butterfly than a carp?

剪蝴蝶比剪鲤鱼多用了这张纸的几分之几？

9. Think about it. How do you add and subtract fractions in the same denominator?

想一想，怎样计算同分母分数加减法？

Lesson three

1. Observe the first group of paper cutting statistical table.

观察第一小组剪纸情况统计表。

2. How many of the works of Wang Fang, Li Jun and Liu Hu account for in the first group?

王芳、李军和刘虎的作品一共占第一小组作品总是的几分之几？

3. What other questions can you ask?

你还能提出什么问题？

4. Observe the second group of paper cutting statistics.

观察第二小组剪纸情况统计表。

5. In the second group's works, what fraction of the works of other categories?

第二小组的作品中，其他类作品占总数的几分之几？

Lesson four

1. With this specification of paper-cut works, arranged into different sizes of the square board.

用这种规格的剪纸作品，布置成大小不同的正方形展板。

2. How many decimeters can the side length of a square board be?

正方形展板的边长可以是多少分米呢？

3. What is the shortest decimeter you can have?

最短可以是多少分米？

4. Replace the word "spring" with a small rectangular piece of paper 3 centimeters long and 2 centimeters wide.

用长3厘米、宽2厘米的小长方形纸片代替“春”字摆摆看。

5. The sides of the squares are 6cm, 12cm and 18cm respectively

摆成的正方形边长分别是6厘米、12厘米、18厘米······

6. Think about it. What is the relationship between the length of a square and the length and width of a rectangle?

想一想，摆成的正方形的边长与长方形的长、宽有什么关系？

7. 6 is both a multiple of 2 and a multiple of 3.

6既是2的倍数，也是3的倍数。

8. 12 is both a multiple of 2 and a multiple of 3. • • • • • • 18

12既是2的倍数，也是3的倍数。18······

9. What other numbers are multiples of both 2 and 3?

还有哪些数既是2的倍数又是3的倍数？

10. Can you find the common multiple or the least common multiple of 12 and 18?

你能找出12和18的公倍数和最小公倍数吗？

11. You can also use short division to find the least common multiple of 12 and 18.

还可以用短除法求12和18的最小公倍数。

Lesson five

1. Interchange of fractions and decimals

分数与小数的互化

2. Convert the following decimal into a fraction.

把下面的小数化成分数。

3. Think about it. How do you turn a decimal into a fraction?

想一想，怎样将小数化成分数？

4. Convert the following fractions into decimals

把下面的分数化成小数

5. Think about it. How do you convert fractions into decimals?

想一想，怎样将分数化成小数？

6. When you divide the numerator by the denominator, you usually keep the decimal to three decimal places.

分子除以分母，除不尽时，得数一般保留三位小数。

Lesson six

1. How tall can I grow?

我能长多高?

2. Students, we are growing up day by day, do you know how tall they can grow?

同学们，大家在一天天长大，你们知道自己能长多高吗？

3. What factors does height have to do with?

身高与哪些因素有关呢？

4. Design Survey Contents

设计调查内容

5. What are the factors that affect height?

影响身高的因素有哪些?

6. What is the relation between your height and the height of your parents?

你的身高与父母的身高有什么关系？

7. What is the relationship between the height of children at all ages and the height of adults?

儿童各年龄段的身高与成年的身高有什么关系？

8. Predict your future height according to the factors that affect your height.

根据影响身高的因素，预测自己将来的身高。

9. After investigation, analysis, communication and summary.

调查后，分析交流、总结。