精品课件

1、16的平方根是的平方根是_ -16的平方根是的平方根是_ 0的平方根是的平方根是_ 4 没有平方根没有平方根 0 一个正数有正负两个平方根一个正数有正负两个平方根,它们互为相反数它们互为相反数; 零的平方根是零零的平方根是零, 负数没有平方根负数没有平方根. 复习：平方根 要做一个体积为要做一个体积为8 的立的立 方体模型方体模型,它的棱要取多少长它的棱。

2、16.3 勾股定理的应用 校园里有一块三角形空地校园里有一块三角形空地, ,现准备在这块空现准备在这块空 地上种植草皮以美化环境地上种植草皮以美化环境, ,已经测量出它的已经测量出它的 三边长分别是三边长分别是13,14,1513,14,15米米, ,若这种草皮每平若这种草皮每平 方米售价方米售价120120元元, ,则购买这种草皮至少需要则购买这种草皮至少需要 支出多少元支出多少元? ? 1。

3、17.317.3实数实数 1、从小学到现在我们都学习了哪些数？、从小学到现在我们都学习了哪些数？ 整数整数 分数分数 有理数有理数 有限小数或无限循环小数有限小数或无限循环小数 2、这些有理数还够用吗？、这些有理数还够用吗？ 在RtABC中，两条直角边AC=BC=2.如 果将RtABC沿斜边AB 上的高CD剪开后， 拼成右图的所示的正方形，那么这个正 方形的边长是多少？ 2 m 2 C A B。

4、勾股定理的应用勾股定理的应用 例例1：如图所示，为了测得湖两岸点：如图所示，为了测得湖两岸点A和和 点点C间的距离，一个观测者在点间的距离，一个观测者在点B设立了设立了 一根标杆，使一根标杆，使ACB=90 测得测得AB=200m,BC=160m根据测量结果，根据测量结果， 求点求点A,C间的距离间的距离 A C B 这个生活中的问题对应的数学问题是什么？这个生活中的问题对应的数学问题是什么？ 。

5、17.5实数的运算 二次根式：二次根式： 我们把形如我们把形如_( ）的式子）的式子 叫做二次根式。叫做二次根式。 如：如： 因为因为 是非负数的算术平方根，所以是非负数的算术平方根，所以 2 a）（ a 积的算术平方根和商的算术平方根的性质 利用上边的规律，我们可以将某些二次根式化利用上边的规律，我们可以将某些二次根式化 简，并且可以方便地进行二。

6、 （1）知识与技能目标 通过现实情境感受在平面上确定物体的位置的多种 方法。并能依据不同情境选择合适的方法。 （2）过程与方法目标 在经历观察、分析的过程中，理解和掌握在平面内 确定物体位置的方法。 （3）情感态度与价值观目标 通过探究平面内物体位置的方法，培养学生探究精 神、合作精神、合作能力，学生在自学的过程中，逐渐 养成良好的自学习惯，增强学生学习数学的心理体验， 产生热爱数学的情感！。

7、17.217.2立方根立方根 ( )3=64 ( )3=1000 ( )3=1000 4 10 10 27 8 ( )3= 0 ( ) 3= 2 3 0 一般地一般地，如果一个数如果一个数x 的立的立 方等于方等于a，即，即x3=a，那么这个数那么这个数x 就叫做就叫做 a的的立方根立方根（也叫做三次（也叫做三次 方根）方根） 2的立方等于多少？。

8、 1 1、我们已经学习过哪些运算？它们中互、我们已经学习过哪些运算？它们中互 为逆运算的是？为逆运算的是？ 答答：加法、减法、乘法、除法、乘方：加法、减法、乘法、除法、乘方 五种运算五种运算。 加法与减法互逆；乘法与除法互逆。加法与减法互逆；乘法与除法互逆。 2 2、乘方有没有逆运算？、乘方有没有逆运算？ 回顾回顾 与与 思考思考 7米米 7米米 ？ 100米米2 ？ （图一）（图。

9、16.3勾股定理的勾股定理的 应用应用 【知识与技能】掌握勾股定理在现实生活中的应【知识与技能】掌握勾股定理在现实生活中的应 用。用。 【过程与方法】经历把实际问题转化成数学问题，【过程与方法】经历把实际问题转化成数学问题， 利用勾股定理解决的过程。利用勾股定理解决的过程。 【情感、态度与价值观】培养学生良好的学习习【情感、态度与价值观】培养学生良好的学习习 惯、合作交流的学习方法、以及学数。

10、Unit 3 Topic 1 Does he speak Chinese? Section C,Name : Jane Age: 12 From: Canada Class: 2 Grade: 7 Phone number: (010)92673388,Jane is my good friend.,Jane,She speaks English.,Name : Sally Age: 13 From: America Class: 2 Grade: 7 Phone number: (010)92674466,Sally is my good friend.,She speaks English, too,Sally,Many students in our class like English a lot, but I like it a little. So my English is not good. Who can help me with it ? My Chinese is OK. Oh, we can help each other.,？,Many students i。

11、Unit 3 Topic 1 Does he speak Chinese?,Section B,351100,福建省莆田市荔城区中山中学,刘百川（收）,北京市仁爱教育研究所,Who is the letter from?,Its from my pen pal, Xiao Liu.,pen pal = pen friend,What does he say in the letter ?,He wants to visit Meizhou Island(岛).,He wants to visit Beijing. want to do sth. 想要做某事 如：I want to buy some toys. want sth. 想要某物 如：He wants a pair of shoes.,Where does he live?,He lives in England.,Does he speak Chinese?,No, he doesnt. He speaks English. But he 。

12、Section A,Unit 3 Getting Together Topic 1 Does he speak Chinese?,T: Excuse me, could you please tell me his name? S: Sure. He is Kangkang. T: Does he come from China? S: Yes, he does. T: Can he speak English? S: Yes. But his English is not very good. T: Could you help him with it? S: No problem.,Have a try!,I have a friend. Id like to tell you something about him. He is Li Wei. He is from China. He often speaks Chinese. He likes English, but his English is not good. He wants to find a pen。

13、Unit 2 Topic 2,What does she look like? Section D,What color are they?,What color is it?,What color are they?,skirt,T-shirt,coat,pants,shoes,dress,cap,Please match.,They dont look the same . She doesnt have black hair. .,Who is Jane? The girl in purple T-shirt is Jane. ,A,B,C,F,pink,yellow,white,brown,Read 2 and fill the table.,T-shirt,yellow,green,white,gray,blue,orange,shoes,Suppose you are Michael, please try to introduce.,My name is Michael. I _ from America. Look at me. I have _。

14、Unit 2 Topic 2,Section C,What does she look like?,Whats this?,What color is it?,What are these?,What color are they?,Look at this photo. What does the boy look like?,a cap,This is a pink cap.,a T-shirt,I want to buy a green T-shirt.,a coat,This coat is black.,pants,Are these pants yours?,dress,This dress is pink. It is very beautiful.,skirt,She often wears a black skirt.,gloves,Whose gloves are these?,skirt,T-shirt,coat,pants,shoes,dress,cap,Please match.,A: _ is this skirt? B: Its 。

15、Unit 2 Topic 2,Section B,What does she look like?,A: What color is it？ B: Its,What color is the flag? Red, white and blue.,Where is he from? He is from Cuba.,What does he look like? He has brown hair and black eyes.,Cuba,1,What color is the flag?,Where is he from?,What does he look like?,Red and white.,He is from Japan.,His hair is black and his eyes are black.,Japan,2,What color is the flag?,Where is she from?,What does she look like?,Red and white.,She is from Canada.,Canada,3,She has 。

16、Unit 2 Topic 2,Section A,What does she look like?,color,black,blond,What color are his eyes? What color is his hair？,blue,blond,What color are his eyes?,blue,What color is her hair?,blond,They look the same. They have black hair and black eyes.,看起来很像。 look 意为“看起来”。,They dont look the same, but they are good friends.,Listen, look and say. Pay attention to the intonation.,Oh, he is my friend, Yukio.,Who is that boy?,1b. Listen and complete the table.,Japan,black,black,black,blue,bl。

17、Unit 2 Topic 1,I have a small nose.,Section D,Can you describe this beautiful girl?,Please describe Li Ping with the key words.,big eyes a small mouth short hair small hands a round face,Name: Li Ping English name: David Age: 12 Gender: boy From: Chongqing Class: 9 Grade: 7 School: Chen Jia High School Phone number: 023-58132200,2,4,3,Listen again and fill.,1. Lin Tao is from China. He has _. 2. Does Tom have long arms? _.,3. Look! Peter _。

18、Unit 2 Topic 1,I have a small nose.,Section C,She has big eyes.,favorite actor ,She has a round face.,His nose is big.,Her mouth is wide.,Shes my sister, Kate. My sister is four years old. She isnt a student. Do you have any sisters or brothers?,sister 姐, 妹,Please notice their looks.,a wide mouth, big eyes,a wide mouth, small eyes,a small mouth, a big nose,big eyes, a wide mouth,a wide mouth, small eyes,big eyes, a small mouth,1,1,2,3,2,3,Guess who is the boy and who is his sister, Amy.,Co。

19、Unit 2 Topic 1 Section A,I have a small nose.,注意他们的外貌特征,Look and learn.,head,face,hair,eye,ear,nose,mouth,neck,Hi! 你看我的眼睛像不像字母e, 鼻子是nose的首字母，嘴像不像mouth的第一个字母m，耳朵里藏着小小的e,还有我的头花可是h形的哦！你能记住我的样子吗？,neck,face,ears,mouth,nose,eyes,hair,head,Listen and match.,ear,head,face,mouth,hair,eye,neck,nose,Hi! Im a girl. I have long hair.,Hi! Im a boy. I have short hair.,a long pencil,a short pencil,Im a boy. I have small eyes.,big,small,The boy。

20、Unit 2 Topic1 I have a small nose.,Section B,A: This is a man. He has small eyes. He is my favorite singer. Guess, who is he? B: Where is she from? A: He is from China. B: I know. He is Li Ronghao.,A,( ),B,( ),C,( ),D,( ),H,( ),arm,hand,leg,foot,F,( ),G,( ),E,( ),Look at the boy and write down the name of each part.,hair,ear,eye,nose,neck,mouth,face,head,My hair is long.,I have long hair.,Its ears are big.,It has two big ears.,Rewrite the sent。