英语五年级下册unit5_what’s_the_weather_like_today_第2课时教学课件
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(3) (am)2= a mΧ 2 = a 2m ; (4) -(x4)3 = - x 4Χ3 = - x12 .
下面计算是否正确?如有错误请改正。
(1)X3·X3=2X3 × X3·X3=X6 (2) X2+X2=X4 × X2+X2=2X2 (3) a4·a2=a6 √
(4) (a3)7=a10 × (5) (X5)3=X15 √
snowy moon star
>>Lead-in
Look and circle
What’s the weather like today?
>>Presentation
Look and imagine
What are they talking about?
>>Presentation
Listen, then ask and answer
20
或不明白意思的单词或句子,
可以把它圈起来,请教同学或
老师!
60 50
40 30
>>Practice
>>Practice
Match and say
A: What’s the weather like/How is the weather today? B: It’s rainy. You’d better take your umbrella.
(10 2 )3 10 2 10 2 10 2 (根据乘方的意义
)
10222(根据同底数幂的乘法法则
1023
) (根据乘法的定义)
106
(102 )3 1023
对于任意底数a与任意正整数m,n,(am )n ?
(am )n amam am (乘方的意义)
n个am
n个m a mm m (同底数幂的乘法法则)
陕旅版 五年级下册
Unit5 What’s the weather like today?
Part A Look and circle Let’s talk
Part C Match and say
>>Review
Magic fingers
weather report sunny
windy cloudy rainy
What’s the weather like today? It’s cloudy. Is it raining in this dialogue? Yes, it is. Does Wu Chen take the umbrella? Yes, he does.
答案
>>Presentation
2.请学生回家观察晚间的天气预报,并用英语记录北
京、上海、广州、兰州和成都5个城市的天气状况。
3.登录“优教同步学习网”,预习B Let’s learn
more。
close
9.8幂的乘方
复习
幂的意义:
n个a
a·a·… ·a
=an
同底数幂乘法的运算性质
:am ·an=am+n(m,n都是正整数 am ·an=(a·a)·… ·a) (a·a·… ·a)
>>Summary
本课所学的重点句型:
-What’s the weather like …? -It’s … e.g. -What’s the weather like today? -It’s sunny.
>>Homework
1.登录“优教同步学习网”,听课文录音并跟读,按
照正确的语音、语调朗读并表演课文对话。
m个a
n个a
= a·a·… ·a =am+n
(m+n)个a
问题:
1.下面的计算对不对?如果不对应该怎样改正?
⑴ x3 x3 2x3; ⑶ x3 x3 2x6;
⑸ aa3 a3;
⑵ x3 x3 x6;
⑷ x3 x3 x9;
2.计算: x yx y2 x y3 x y6
1.试一试:读出式子 32 3; a2 5.
rainy
sunny
snowy
>>Practice
Ask and answer
What’s your favorite season? spring
My favorite season is… What’s the weather like in…
summer autumn winter
spring/summer/autumn/winter? It’s… warm/cold/hot/cool.
的a可代 表一个
不同点是: 同底数幂的乘法是指数相加数;、字
母、式
而幂的乘方是指数相乘. 子等.
[(am )n ]p ?amnp (m, n, p为正整数)
例1:计算:
(1) (103)5; (3) (am)2;
(2) (a4)4; (4) -(x4)3.
解: (1) (103)5=103Χ5 = 1015 ; (2) (a4)4=a4Χ4=a16;
2. 32 3 表示什么?
a2 3表示什么?
am 3 表示什么?
3.根据乘方的意义及同底数幂的乘法填空,看看计 算的结果有什么规律:
⑴ (32 )3 32 32 32 36;
⑵ (a2 )3 a2 a2 a2 a6 ;
⑶ (am )3 a m a m a m a3m (m是正整数).
Let’s talk
Wu Chen: What’s the weather like today, Mom? Mom: It’s cloudy. Dad: No. It’s not cloudy. It’s rainy.
Wu Chen: Oh, look! It’s raining now. Mom: Take your umbrella with you.
Wu Chen: OK. See you, Mom and Dad! Mom&Dad: See you, dear!
点击小喇叭或文本框都可以播放音频
>>Practice
Read it by yourselves for one minute. 自读对话一分钟。
10
Tips:
当你自己朗读时,遇到不会读
a mn (乘法的定义)
(am )n amn (m,n都是正整数).
幂的乘方,底数 不变 ,指数 相乘 .
想一想:
同底数幂的乘法法则与幂 的乘方法则有什么相同点 和不同点?
幂的乘方与同底数幂的乘法的异同:
ຫໍສະໝຸດ Baidu
am an amn;(am )n amn(m, n为正整数公)式中
相同点是 都是底数不变
下面计算是否正确?如有错误请改正。
(1)X3·X3=2X3 × X3·X3=X6 (2) X2+X2=X4 × X2+X2=2X2 (3) a4·a2=a6 √
(4) (a3)7=a10 × (5) (X5)3=X15 √
snowy moon star
>>Lead-in
Look and circle
What’s the weather like today?
>>Presentation
Look and imagine
What are they talking about?
>>Presentation
Listen, then ask and answer
20
或不明白意思的单词或句子,
可以把它圈起来,请教同学或
老师!
60 50
40 30
>>Practice
>>Practice
Match and say
A: What’s the weather like/How is the weather today? B: It’s rainy. You’d better take your umbrella.
(10 2 )3 10 2 10 2 10 2 (根据乘方的意义
)
10222(根据同底数幂的乘法法则
1023
) (根据乘法的定义)
106
(102 )3 1023
对于任意底数a与任意正整数m,n,(am )n ?
(am )n amam am (乘方的意义)
n个am
n个m a mm m (同底数幂的乘法法则)
陕旅版 五年级下册
Unit5 What’s the weather like today?
Part A Look and circle Let’s talk
Part C Match and say
>>Review
Magic fingers
weather report sunny
windy cloudy rainy
What’s the weather like today? It’s cloudy. Is it raining in this dialogue? Yes, it is. Does Wu Chen take the umbrella? Yes, he does.
答案
>>Presentation
2.请学生回家观察晚间的天气预报,并用英语记录北
京、上海、广州、兰州和成都5个城市的天气状况。
3.登录“优教同步学习网”,预习B Let’s learn
more。
close
9.8幂的乘方
复习
幂的意义:
n个a
a·a·… ·a
=an
同底数幂乘法的运算性质
:am ·an=am+n(m,n都是正整数 am ·an=(a·a)·… ·a) (a·a·… ·a)
>>Summary
本课所学的重点句型:
-What’s the weather like …? -It’s … e.g. -What’s the weather like today? -It’s sunny.
>>Homework
1.登录“优教同步学习网”,听课文录音并跟读,按
照正确的语音、语调朗读并表演课文对话。
m个a
n个a
= a·a·… ·a =am+n
(m+n)个a
问题:
1.下面的计算对不对?如果不对应该怎样改正?
⑴ x3 x3 2x3; ⑶ x3 x3 2x6;
⑸ aa3 a3;
⑵ x3 x3 x6;
⑷ x3 x3 x9;
2.计算: x yx y2 x y3 x y6
1.试一试:读出式子 32 3; a2 5.
rainy
sunny
snowy
>>Practice
Ask and answer
What’s your favorite season? spring
My favorite season is… What’s the weather like in…
summer autumn winter
spring/summer/autumn/winter? It’s… warm/cold/hot/cool.
的a可代 表一个
不同点是: 同底数幂的乘法是指数相加数;、字
母、式
而幂的乘方是指数相乘. 子等.
[(am )n ]p ?amnp (m, n, p为正整数)
例1:计算:
(1) (103)5; (3) (am)2;
(2) (a4)4; (4) -(x4)3.
解: (1) (103)5=103Χ5 = 1015 ; (2) (a4)4=a4Χ4=a16;
2. 32 3 表示什么?
a2 3表示什么?
am 3 表示什么?
3.根据乘方的意义及同底数幂的乘法填空,看看计 算的结果有什么规律:
⑴ (32 )3 32 32 32 36;
⑵ (a2 )3 a2 a2 a2 a6 ;
⑶ (am )3 a m a m a m a3m (m是正整数).
Let’s talk
Wu Chen: What’s the weather like today, Mom? Mom: It’s cloudy. Dad: No. It’s not cloudy. It’s rainy.
Wu Chen: Oh, look! It’s raining now. Mom: Take your umbrella with you.
Wu Chen: OK. See you, Mom and Dad! Mom&Dad: See you, dear!
点击小喇叭或文本框都可以播放音频
>>Practice
Read it by yourselves for one minute. 自读对话一分钟。
10
Tips:
当你自己朗读时,遇到不会读
a mn (乘法的定义)
(am )n amn (m,n都是正整数).
幂的乘方,底数 不变 ,指数 相乘 .
想一想:
同底数幂的乘法法则与幂 的乘方法则有什么相同点 和不同点?
幂的乘方与同底数幂的乘法的异同:
ຫໍສະໝຸດ Baidu
am an amn;(am )n amn(m, n为正整数公)式中
相同点是 都是底数不变