第四单元

Unit four

Industrious little bee勤劳的小蜜蜂

Addition and subtraction within ten thousand

万以内的加减法(一)

Lesson one

1.     32 are squires, 45 are guards.

32只是侍从，45只是卫兵。

2.How many squires and guards are there?

侍从和卫兵一共有多少只？

3. Column: How much is thirty-two plus forty-five?

列式：32+45=（  ）

4. Method one: composition of numbers

方法一：数的组成 

30+40=70   2+5=7   70+7=77

5. Method two: first add two digits to the whole ten, then add one digit.

方法二：先用两位数加整十数，再加一位数。

32+40=72    72+5=77

6. How many more guards than squire?

卫兵比侍从多多少只？

7. What's forty-five minus thirty-two?

列式：45-32=（   ）

8. Method one: composition of numbers

方法一：数的组成  

40-30=10   5-2=3  10+3=13

9. Method 2: Subtract two digits from ten, then subtract one.

方法二：先用两位数减整十数，再减一位数。

45-30=15   15-2=13

10. Let's do some exercises together!

我们一起来做练习吧！

Lesson two

1. Look at the picture, how many birds are there in Team 1 and Team 2?

观图，一队和二队一共有多少只？

2. What's three hundred and twenty plus two hundred and ten?

320+210=(    )

3. Think about it: what method can be used to calculate it?

想一想：可以用什么方法计算？

4. I'll do it in vertical form.

我会用竖式算。

5. How many fewer are team two than team one?

二队比一队少多少只？

6. How many are there in Team 2 and Team 3?

二队和三队一共有多少只？

7. Tip: the same digit to align.

提示：相同数位要对齐。

8. About a few hundred in teams three and four?

三、四两队大约有几百只？

9. I think of it this way: 86 is close to 100,103 is close to 100,100+100=200,86+103 is about 200.

我这样想：86接近 100,103接近100,100+100=200,86+103的结果大约是200。

10. There were about 200 in teams three and four.

三、四两队大约有200只。

11. Eighty-six plus one hundred and three is about two hundred

86+103≈200      读作：86+103约等于200。

12. Let's do some exercises together!

我们来一起做练习吧！

Lesson three

1. From home to the orchard 592 meters. 384 meters from home to garden.

从家到果园592米。从家到花园384米。

2. How many meters are there from the orchard to the garden?

从果园到花园一共有多少米？

3. What's five hundred ninety-two plus three hundred eighty-four?

592+384=（   ）

4. Let's do it vertically

用竖式计算

5. When we fill the tens place, we carry one to the tens place.

个位满十要向十位进1。

6. What if I add the tens digit up to 10?

十位上的数相加满10，怎么办呢？

7. The second team is much less than the first team?

第二队比第一队少多少只？

8. What's five hundred eighteen minus two hundred twenty-seven?

518-227=（   ）

9. Assess first, and then make a vertical calculation.

先估一估，再列竖式计算。

10. 1 minus 2 in the tens place is not enough. What do we do?

十位上1减2不够减，怎么办？

11. How many more meters does it take to fly from home to orchard than from home to garden?

从家到果园比从家到花园要多飞多少米？

12. What do you pay attention to when you add and subtract vertically?

用竖式计算加减法时要注意什么？

Lesson four

1. Check the honey production and use records.

去检查一下蜂蜜的生产和使用记录对不对。

2.How to check?

怎样检查呢？

3. What's five hundred seventy-three plus three hundred eighteen?

573+318=（   ）

4. We can check that out.

我们可以验算一下。

5. Method one: swap the positions of the two addends...

方法一：交换两个加数的位置……

6. Method two: and subtract one of the addends...

方法二：和减其中的一个加数……

7. What's eight hundred ninety-one minus two hundred sixty-four?

891-264=(   )

8. Check calculation method: difference plus or minus number......

验算方法：差加减数……       

Minuend subtraction...

被减数减差……

9. When calculating, be sure to develop the good habit of checking.