跟讀練習: Adding Fractions With Unlike Denominators - 通過影片學習英語口語

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In this video, we're going to talk about how to add two fractions.
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So let's start with this example.
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2 over 3 plus 3 over 4.
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So how can we add these two fractions?
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The first thing you can do is multiply the denominators of the fractions.
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3 times 4 is 12. And then cross multiply.
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2 times 4 is 8, and then multiply 3 times 3, and that will give you 9.
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And then you could add 8 and 9.
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8 plus 9 is 17.
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So we get the answer 17 over 12.
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And so this is our answer as an improper fraction.
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Now, let's try another example.
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So let's add 5 over 3 plus 1 over 2.
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So let's follow the same technique.
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3 times 2 is 6. And then cross multiply.
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5 times 2 is 10.
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3 times 1 is 3.
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And then we're going to add 10 plus 3.
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So 10 plus 3 is 13.
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So the answer is 13 over 6. by the way
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if you want more videos on fractions let's say how to subtract fractions how to multiply
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or divide fractions check out the description section of this video i'm going to post some links there
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that you might find useful
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but now let's get back to this video let's work on another problem
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so now it's your turn go ahead and add the following fractions 2 over 5 plus 1 over 4
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And also try this example, 3 over 7 plus 5 over 9.
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Feel free to pause the video and try those examples.
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So let's start with the first one.
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So first we're going to multiply 5 and 4.
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5 times 4 is 20. And then cross multiply.
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2 times 4 is 8.
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5 times 1 is 5.
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And now we can add 8 plus 5 is 13.
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So the answer is 13 over 20.
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Now let's try the example below.
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So let's multiply 7 by 9.
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7 times 9 is 63. And then cross multiply.
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3 times 9 is 27.
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And 7 times 5 is 35.
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So now we'll need to add 27 and 35.
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So you can use a calculator or you can do it the old-fashioned way.
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Let's do it the old-fashioned way.
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5 plus 7 is 12, so we need to write the 2, carry over the 1.
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And then 3 plus 2 plus 1 is 6.
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So 27 plus 35 is 62.
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So the final answer for that example is 62 divided by 63.
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So at this point, you know how to add 2 fractions.
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But what if you need to add, let's say, 3 fractions?
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What should you do?
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So before we go into this example, I want to show you another example of adding 2 fractions but using a different method.
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So let's start with this problem, 3 over 8 plus 5 over 7.
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So let's begin by using the method that you're familiar with
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and then we'll use a new method to get the same answer.
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So what we did before is multiply the two denominators of the fractions.
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8 times 7 is 56.
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And then we would cross multiply.
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3 times 7 is 21.
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And 8 times 5 is 40.
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And then we would add 21 plus 40 is 61.
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So our answer for this example would be 61 over 56.
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Now here's another method which is useful if you're adding multiple fractions.
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So what you want to do is get a common denominator of 56.
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In order to do so, the fraction on the left you need to multiply the top and the bottom by 7.
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And for the fraction on the right, multiply the top and the bottom by 8.
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So this would give you a common denominator of 56.
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So 3 times 7 is 21, and 7 times 8 is 56.
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5 times 8 is 40, and on the bottom, 7 times 8 is 56.
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Now whenever you're adding two fractions, if the denominator is the same, then you're allowed to add the numerators of the two fractions.
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So 21 plus 40 is 61.
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And thus, we're going to get the same answer of 61 over 56.
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This technique works if you're adding, let's say, three fractions or even four fractions.
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Now, let's try this example.
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2 over 5 plus 3 over 4 plus 1 over 3.
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So the first thing we need to do is identify a common denominator that we need to get to.
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So we need to find the least common multiple of 5, 4, and 3.
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How can we do so?
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Well, a simple way is to multiply 5 times 4 times 3.
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You could use any common multiple.
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It doesn't really have to be the least common multiple.
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But if you could find the least common multiple, then it's going to be easier.
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But let's keep it simple.
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so 5 times 4 times 3
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5 times 4 is 20 20 times 3 is 60 so 60 is a common multiple of 5, 4, and 3 it might even be the least common multiple
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and I think it is so what I'm going to do now is take 60 and divide it by 5
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60 divided by 5 is 12 so therefore I'm going to multiply the second fraction, I mean the first fraction, by 12.
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So that will give me a common denominator of 60.
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Now 60 divided by 4 is 15.
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So I need to multiply the second fraction, the top and the bottom, by 15.
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Whatever you multiply the bottom of a fraction by, you need to do so also to the top.
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Now 60 divided by 3 is 20.
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So I'm going to multiply the third fraction by 20 over 20.
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12 times 2 is 24 and we know that 12 times 5 is 60.
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15 times 3 is 45 and 15 times 4 is 60.
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20 times 1 is 20.
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20 times 3 is 60.
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So notice that we have a common denominator of 60.
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So now all we need to do is add up the three numerators.
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So let's find a sum of 45, 24, and 20.
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5 plus 4 is 9.
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4 plus 2 plus 2 is 8.
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So 24 plus 45 plus 20 is 89.
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So our answer for this problem is 89 over 60.
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So that's how you can add three fractions together.
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Now let's try another example.
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So now it's your turn.
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Go ahead and add 1 over 4 plus 5 over 6 plus 1 over 2.
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So let's identify the least common multiple of 4, 6, and 2.
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Multiples of 6 are 6, 12, 18, 24, and so forth.
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Multiples of 4 are 4, 8, 12, 16, 20.
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Multiples of 2 are 2, 4, 6, 8, 10, 12, 14.
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So which of these are the least common multiple of 2, 4, and 6?
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Notice that 12 is the lowest common number or lowest common multiple of 2, 4, and 6.
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So therefore, 12 is the least common multiple.
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Now, 12 divided by 4 is 3.
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So I'm going to multiply this fraction by 3 over 3.
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And 12 divided by 6 is 2.
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So I'm going to multiply this second fraction by 2 over 2.
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And 12 divided by 2 is 6.
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So I'm going to multiply this fraction.
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Let's change that color. By 6 over 6.
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So I'm going to get 3 over 12 plus 2 times 5 is 10.
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2 times 6 is 12.
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and then 6 times 1 is 6, 6 times 2 is 12.
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So now we need to add.
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3 plus 10 is 13.
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13 plus 6 is 19.
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So the final answer is 19 over 12.
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So that is it for this video.
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Be sure to check out my next video on subtracting fractions.
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I'm going to post some links in the description section of this video, so feel free to take a look at that.
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Thank you.

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本節課你將練習什麼?

這節課我們通過學習“異分母分數相加”的方法,同時提升英語聽力和口語能力。你會跟著影片中的講解,一邊理解數學知識,一邊練習英語表達,尤其是如何清晰描述計算步驟。通過影子跟讀(shadow speech),你能逐漸跟上影片的語速,提高英語發音的準確性,還能學會用英語講解數學問題呢!

核心詞彙與表達

  • fractions:分數
  • denominators:分母
  • cross multiply:交叉相乘
  • improper fraction:假分數
  • carry over:進位
  • shadow speech:影子跟讀

影子跟讀練習技巧

影片中的講解語速適中,語氣清晰,非常適合進行英語影子跟讀(英語影子跟讀)練習。建議你先完整聽一遍,熟悉內容後,嘗試滯後1-2秒跟讀。注意模仿說話人的語調,比如講解計算步驟時的停頓和重音(如“cross multiply”中的重音在“cross”)。練習時可以把重點放在“如何用英語描述分數加法”上,比如“3 times 4 is 12”“add 8 and 9”這樣的表達。堅持用shadow peaks方法練習,不僅能提高英語發音,還能讓你更自信地用英語表達數學思維。別擔心出錯,慢慢來,你會越練越好的!

影片中的語法

說話人最常用的結構,並附上影片中的原話:

結構影片中的用法
最高階 the -est / the most … — 一組中最高或最低的the least common · the lowest
用 “might / may” 表可能 might/may + 動詞 — 有可能但不確定的事might find · might even be
“going to” 表將來 be going to + 動詞 — 計劃或明顯即將發生的事we're going to talk · we're going to add · i'm going to post
義務:must / have to / need to 表示某事是必要的need to add · need to write · need to multiply

什麼是跟讀法?

跟讀法 (Shadowing) 是一種有科學依據的語言學習技巧,最初開發用於專業口譯員的培訓,並由多語言者Alexander Arguelles博士普及。這個方法簡單而強大:您在聽英語母語原聲的同時立即大聲重複——就像是一個延遲1-2秒緊跟說話者的影子。與被動聽力或語法練習不同,跟讀法強迫您的大腦和口腔肌肉同時處理並模模擬實的講話模式。研究表明它能顯著提高發音準確性,語調,節奏,連讀,聽力理解和口語流利度——使其成為雅思口語備考和真實英語交流最有效的方法之一。

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