第六单元

Unit 6

The performance of group gymnastics -- factors and multiples

六 团体操表演——因数与倍数

Lesson 1

Twelve students performed ball exercises.

12个同学做球操表演。

What questions can you ask?

你能提出什么问题？

Cooperative exploration

合作探索

How do you line up?

1. 可以怎样排队？

2 times 6 is 12, 2 is a factor of 12, 6 is also a factor of 12; 12 is a multiple of 2, 12 is a multiple of 6.

2×6＝12, 2是12的因数，6也是12的因数；12是2的倍数，12 也是6 的倍数。

Can you find the factors of 24?

你能找出24的因数吗？

I find that a number has a finite number of factors, the smallest factor is 1, and the largest factor is itself.

我发现一个数的因数的个数是有限的，最小的因数是1，最大的因数是它本身。

What are some multiples of 4? Can you look for it?

4的倍数有哪些？你能找一找吗？

Multiples of 4 are: 4, 8, 12, 16...

4 的倍数有：4、8、12、16……

I find that the number of multiples of a number is infinite, the smallest is itself, there is no largest multiple.

我发现一个数的倍数的个数是无限的，最小的是它本身，没有最大的倍数。

When we're dealing with factors and multiples, we don't usually talk about 0.

在研究因数和倍数的时候，一般不讨论0。

Lesson 2

circle dance     human pyramid      social dance

圆圈舞          叠罗汉              交谊舞

What questions can you ask?

你能提出什么问题？

Cooperative exploration

合作探索

How many people can be sent to the ballroom dance and the circle dance?

1. 交谊舞和圆圈舞表演可以分别选派多少人参加？

You can study it with a hundred table.

可以用百数表来研究。

In natural numbers, the numbers that are multiples of 2 are called even, and the numbers that are not multiples of 2 are called odd.

自然数中，是2 的倍数的数叫作偶数，不是2 的倍数的数叫做奇数。

How many people are allowed to take part in the pyramid show?

2. 叠罗汉表演可以选派多少人参加？

Find a number of multiples of 3 and count them, and see how many beads are used. What did you find?

找几个3的倍数用计数器表示出来，看看各用了几个珠子。你有什么发现？

If the sum of the digits in a number is a multiple of 3, the number is a multiple of 3.

一个数各个数位上数的和是3的倍数，这个数就是3的倍数。

Lesson 3

What questions can you ask?

你能提出什么问题？

Cooperative exploration

合作探索

1. The number of people lined up in each side is 24, 25, 40, 35 and 32. What are the characteristics of these numbers?

1. 排成各个方队的人数分别是24、25、40、35、32，这些数有什么特点呢？

Like two, three, five... Thus, a number that has only two factors, 1 and itself, is called a prime number. Like four, six, eight... A number that has other factors than 1 and itself is called a composite number. 1 has only one factor and is neither prime nor compound
The number.

像2、3、5……这样只有1和它本身两个因数的数，叫做质数(素数)；像4、6 、8 ……这

样除了1和它本身，还有其他因数的数，叫做合数；1只有1个因数，既不是质数也不是合

数。

2. Can you write 30 as a multiplication of several prime numbers?

3. 你能把30 写成几个质数相乘的形式吗？

30 can be written as a multiplication of the prime numbers 2, 3, and 5, which are called prime factors of 30.

30 可以写成质数2、3、5相乘的形式，2、 3、 5叫做30的质因数。

The expression of a composite number as a product of prime numbers is called the decomposition of prime factors.

把一个合数用质数相乘的形式表示出来，叫作分解质因数。