第四单元

Unit 4

Walking into the zoo -- simple equation

四 走进动物园——简易方程

Lesson 1

The bowl of rice noodles weighs 20 grams.

盛米粉的碗重20克。

The panda needs to be fed a bowl of rice noodles at a time.

这只熊猫一次需要喂一碗米粉。

What questions can you ask?

你能提出什么问题？

Cooperative exploration

合作探索

How many grams does the rice noodles weigh?

1. 米粉重多少克？

We do this with the help of scales.

我们借助天平来研究。

If the rice noodles weigh x grams, then the bowl and the rice noodles together weigh (20+x) grams.

如果米粉重x克，那么碗和米粉共重(20＋x)克。

It's heavy on the left.

左边重了。

Twenty plus x is greater than fifty.

20＋x＞50

It's heavy on the right.

右边重了。

Twenty plus x is less than one hundred.

20＋x＜100

It’s balanced.

平衡了！

Twenty plus x equals to seventy.

20＋x＝70

Rice noodles weigh 50 grams.

米粉重50克。

Twenty plus x is equal to 70. It is a equation.

20＋x＝70是等式。

2. Can you equate the following equalities in the scales?

2. 你能用等式表示下面天平中的等量关系吗？

Like 20+x = 70, 2x = 150, 3x+10 = 100... Such an equation with unknowns is called an equation.

像20＋x＝70、2x＝150、3x＋10＝100……这样含有未知数的等式，叫做方程。

Lesson 2

Golden Monkey House: The cage weighs 150 grams.

金丝猴馆：笼重150 克。

What questions can you ask?

你能提出什么问题？

Cooperative exploration

合作探索

1. How many grams does a baby golden monkey weigh?

1. 小金丝猴重多少克？

Baby golden monkey weight + cage weight = 500g

小金丝猴的体重＋ 笼重 ＝500克

If x is the weight of a baby golden monkey, can you solve the equation?

如果用x 表示小金丝猴的体重，你能列方程解答吗？

X plus one hundred and fifty equals to five hundreds

x＋150＝500

If you add or subtract the same number to both sides of an equation, it still works. That's a property of the equation.

等式两边同时加上或减去同一个数，等式仍然成立。这是等式的性质。

Can you solve for x minus 10 is equal to 70?

你会解x－10＝70吗？

Would you say 100x minus x = 80?

你会100x－x＝80吗？

The value of the unknowns that make the left and right sides of the equation equal is called the solution of the equation. The process of finding a solution to an equation is called solving the equation.

使方程左右两边相等的未知数的值，叫作方程的解。求方程解的过程叫作解方程。

Lesson 3

My weight is 2.4 kilograms, three times as much as you.

我的体重是2.4千克，相当于你的3倍。

What questions can you ask?

你能提出什么问题？

Cooperative exploration

合作探索

1. How many kilograms does the parrot weigh?

1. 鹦鹉重多少千克？

The mass of the parrot times 3 = the mass of the golden monkey

鹦鹉的质量×3＝金丝猴的质量

If x is the mass of the parrot, can you write the equation to solve it?

如果用x 表示鹦鹉的质量，你能列方程解答吗？

Three x equals to two point four

3x＝2.4

If you multiply or divide both sides of an equation by the same number (zero does not divide), the equation still holds. That's also a property of the equation.

等式两边同时乘或除以同一个数(0不作除数)，等式仍然成立。这也是等式的性质。

Now I'm going to solve the equation 3x is equal to 2.4.

现在我会求方程3x＝2.4的解了。

Let me check..

我来检验……

Lesson 4

There are 25 red-crowned cranes.

有25只丹顶鹤。

There are nine more red-crowned cranes than egrets.

丹顶鹤比白鹭多9只。

There are 60 white swans. There are four times as many white swans as black swans.

有60只白天鹅，白天鹅的只数是黑天鹅的4倍。

What questions can you ask?

你能提出什么问题？

Cooperative exploration

合作探索

1. How many egrets are there?

1. 白鹭有多少只？

First, analyze the quantitative relationship between red-crowned cranes and egrets, and write the equivalent relationship formula.

先分析丹顶鹤与白鹭之间的数量关系、写出等量关系式。

The number of egrets plus the number of more = the number of red-crowned cranes

白鹭的只数＋ 多的只数＝ 丹顶鹤的只数

Then, according to the equivalence relationship, set up the solution equation.

再根据等量关系列方程解答。

2. How many black swans are there?

2. 黑天鹅有多少只？

I can figure out the equivalence relationship based on the question.

根据题意，我能找出等量关系。

The number of black swans times 4 is equal to the number of white swans

黑天鹅的只数×4＝白天鹅的只数

Equations can be set up according to equivalence relations.

根据等量关系可以列出方程。

Think about it: how can you solve a problem by writing equations?

想一想：怎样用列方程的方法解决问题？

Lesson 5

There are 38 sika deer in all.

一共有38 只梅花鹿。

The number of Sika deer is three times more than that of giraffe.

梅花鹿的只数比长颈鹿的3倍多2只。

The zoo has a total of 24 Siberian tigers and white tigers.

动物园中一共有东北虎和白虎24只。

The number of  Siberian tigers is seven times that of white tigers.

东北虎的只数是白虎的7倍。

What questions can you ask?

你能提出什么问题？

Cooperative exploration

合作探索

How many giraffes are there?

1. 长颈鹿有多少只？

First, the relationship between the number of sika deer and the number of giraffes is analyzed.

先分析梅花鹿的只数与长颈鹿的只数之间的关系。

The number of giraffes times three plus the number of more equals to the number of sika deer

长颈鹿的只数×3＋多的只数＝梅花鹿的只数

Then, according to the equivalence relationship, set up the solution equation.

再根据等量关系列方程解答。

Let me check.

我来检验。

2. How many white tigers and how many Siberian tigers are there?

2. 白虎和东北虎各有多少只？

The number of Siberian tigers plus the number of white tigers equals to the total number

东北虎的只数＋白虎的只数＝总只数

Seven x and one x is add up to eight x.

7个x 与1个x 合起来等于8个x。