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用美国小孩的方法学英语最有效:数学运算

用美国小孩的方法学英语最有效(17):简单数学运算
Multiplication and Division 乘法和除法 Multiply with 2 and 6 2 与 6 的乘法 (1) Joan buys six pairs of gloves. How many gloves in all does she buy? Solve the problem in 3 ways. Explain them. (1) 琼买了 6 双手套。她总共买了多少只手套?用三种方法回答这个问题,并讲解它们。 (2) Solve each problem by addition, skip-counting and multiplication. (2) 用加法、跳跃计数和乘法解答以下各题。 ①Six houses each have six windows. How many windows are there in all? ①有 6 间房子,每间房都有 6 扇窗。请问总共有多少扇窗? ②How many legs do three frogs have? ②3 只青蛙共有几条腿? ③If you have five dimes, how much money do you have? ③如果你有 6 个 10 的硬币,那么你有多少钱? 答 案 1.2+2+2+2+2+2= 12 She can add. (她可以用加法) 6×2=12 2, 4, 6, 8, 10, 12

She can skip-count. (她可以用跳数) She can multiply.(她可以用乘法) 2.①6+6+6+6+6+6=36 ②4+4+4=12 4, 8, 12

6,12, 18, 24, 30, 36 3×4=12

6×6=36

③10+10+10+10+10+10=60

10, 20, 30, 40, 50, 60

10×6=60

The Meaning of Division 除法的意义 We use division when we want to separate objects into groups of equal size. 当我们想把物体分成相等的大小时,我们可以用除法。 The answer to a division problem is the quotient. 对于除法问题的答案叫做商数。

(1) The lunchroom can seat 72 people at the same time. There are 12 tables. Each table seats the same number of people. How many people can sit at each table? (1) 快餐店一次能容纳 72 个人。店里有 12 张桌子,每张桌子所坐人数相同,请问一张桌 子能坐多少个人? Number sentence: ___________ . 算术运算式:___________ 。 Answer: ___________ people. 答案:___________ 人。 (2) Each baseball team in the league has 9 players. There are 108 players in all. How many teams are there? (2) 每支棒球队有 9 个队员。俱乐部里总共有 108 个队员,请问这个俱乐部有多少支棒球 队? Number sentence: ___________ . 算术运算式:___________ 。 Answer: ___________ teams 答案:___________ 队。 (3) The pet store has 32 hamsters. They keep the same number of hamsters in each cage. There are 8 cages. How many hamsters are in each cage? (3)宠物店里共有 32 只仓鼠。每个笼子里放有相同数目的仓鼠,共有 8 个笼子。请问每个 笼子里有几只仓鼠? Number sentence: ___________ . 算术运算式:___________ 。 Answer: ___________ hamsters. 答案:___________ 只仓鼠。 答 案 (1) 72÷12=6, (2) 108÷9=12, (3) 32 ÷ 8=4 [注] 基本的数学乘除法的读法: 3×5 = 15 Three multiplied by five makes fifteen.或 Three times five equals fifteen . 6 people 12 teams 4 hamsters.

15÷3=5 Fifteen divided by three equals five.注意 fifteen 后千万不可加上 is,念 成 is divided by。

Multistep Problems 多重运算题 A multistep problem is a problem which requires more than one step in order to solve it. 多重运算问题是指要用多于一个步骤来解题。 (1) Jack bought 5 picture books that cost $3 each. He also bought 4 storybooks that cost $5 each. How much did Jack spend on books? (1) 杰克买了 5 本小人书,每本 3 美元。他还买了 4 本故事书,每本 5 美元。请问杰克买 书共花了多少钱? (2) Susan has 4 rows of 8 stamps in her stamp collection. She wants to triple her collection. How many stamps will Susan have when she triples her collection? (2) 苏珊收集的邮票有 4 排,每排有 8 张。她想将她的收藏品翻三倍。请问收藏品翻三倍 后,苏珊会有多少张邮票? (3) Lily had 47 photographs to put in her album. When she divided them evenly onto 11 pages, she had 3 left over. How many photographs did Lily put on each page? (3) 莉莉把 47 张照片放进她的相册里,她把这些照片平均分成 11 页时,手里还剩 3 张照 片。请问莉莉每页放多少张照片? 答 案 (1) (2) (3) (3×5)+(5×4) =35 (8×4) ×3 =96 (47-3)÷11=4