Unit 2 Happy a big break -- Two digit times one digit 快乐大课间——两位数乘一位数 Lesson 1 The dancing students of Class 1 Grade 3 are divided into 2 groups, and each group has 20 students. 三(1)班跳舞的同学分2组，每组20人。 The dancing students of Class 2Grade 3 are divided into 3 groups, and each group has 12 students. 三(2)班跳舞的同学分3组，每组12人。 What questions can you ask? 你能提出什么问题？ Cooperative exploration 合作探索 How many dancers are there in class Class 1 Grade 3 ? 三(1)班跳舞的一共有多少人？ What is twenty by two? Twenty by two is _____(people) 20×2＝ _______(人) I'll swing it with the stick. So how do we do that? 我用小棒摆一摆。怎样算呢？ 20 by 2, that means you add two 20's, 20 plus 20 is 40. 20 ×2，表示2 个20相加，20＋ 20＝ 40。 Two tens times two is four tens, and four tens is forty. 2 个十乘2得4 个十，4个十是40。 How many dancers are there in class 2 Grade 3? 三(2)班跳舞的一共有多少人？ What is twelve by three? twelve by three is _____(people) 12×3＝_______(人) I'll swing it with a block of wood. So how do we do that? 我用木块摆一摆。 怎样算呢？ I think this way: ten by three ×3 = 30 2×3 = 6...... 我这样想：10×3＝30 2×3＝6 ...... You can do it in vertical form. 可以用竖式计算。 Can you calculate 4 times 21? 你会计算4×21吗？ You can change the positions of factors ..... 可以交换因数的位置...... Lesson 2 Performing Rhythmic Gymnastics are 5 rows, each row has 19 people . 表演艺术体操的排5行，每行19人。 There are two groups of performing fan dance,each row has 29 people. 表演扇子舞的有2组，每组29人。 What questions can you ask? 你能提出什么问题？ Cooperative exploration 合作探索 How many people are there performing the fan dance? 表演扇子舞的一共有多少人？ What is twenty- nine times two? Twenty- nine times two is _____(people) 29×2＝_________(人) I'll swing it with the stick. 我用小棒摆一摆。 I'll do it in vertical form. 我用竖式计算。 It's easy to write the vertical form. 这样写竖式简便。 Can you calculate 59 times 7 and 8 times 25? 你会计算59×7 和8×25吗？ How many should I put in the blank? □里应该填几？ Think about it. What should I pay attention to when I calculate multiplication? 想一想，计算乘法时应注意些什么？ Lesson 3 There were 18 hula hoops in Grade one. 一年级转呼啦圈的有18人。 The number of hula hoops in Grade two is twice as many as that Grade one. 二年级转呼啦圈的人数比一年级的2倍多5人。 The number of hula hoops in Grade three was three times less than that in Grade one by two. 三年级转呼啦圈的人数比一年级的3倍少2人。 What questions can you ask? 你能提出什么问题？ Cooperative exploration 合作探索 How many people turn the hula hoop in Grade two. 二年级转呼啦圈的有多少人？ Draw line segment diagrams to sort out conditions and problems. 画线段图来整理条件和问题。 First draw a line segment to show the number of students in Grade one, and then draw a line segment to show...... 先画一条线段表示一年级的人数，再画一条线段表示...... So let's figure out what 2 times the number of first graders is. 先求一年级人数的2倍是多少。 Eighteen times two is thirty six(people) 18×2＝36(人) To figure out again,how many people are there to turn hula hoops in Grade two? 再求二年级有多少人。 Thirty-six plus five is+5 forty one(people) 36＋5＝41(人) Answer: There are 41 people who turn hula hoops in Grade two. 答：二年级转呼啦圈的有41人。 There were 41 people turning hula hoops in Grade two. 二年级转呼啦圈的有41人。 How many people turn hula hoops in Grade two. 三年级转呼啦圈的有多少人？ I use a line segment...... 我用线段...... So let's figure out what 3 times the number of first graders is. 先求一年级人数的3倍是多少。 Eighteen times three is fifty-four(people) 18×3＝54(人) To figure out again,how many people are there to turn hula hoops in Grade two? 再求三年级转呼啦圈的有多少人。 fifty-four minus two is fifty two(people) 54－2＝52(人) Answer: There are 32 people who turn hula hoops in Grade three. 答：三年级转呼啦圈的有52人。 |
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