シャドーイング練習: Adding Fractions With Unlike Denominators - 動画で英語スピーキングを学ぶ

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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.

この動画で身につくスキル

分数の足し算の基本的な方法を学ぶだけでなく、英語で数学の説明を聞き取るリスニング力も鍛えられます。また、「cross multiply」「improper fraction」などの数学用語の英語表現を覚え、自然なスピーチのリズムを掴むことができます。これらはIELTSスピーキング対策にも役立つ実践的なスキルですよ!

聞き取りに注意すべき音のつながり

動画の中では、「add two fractions」の「add two」が「アドゥー」とつながって発音されたり、「multiply the denominators」の「multiply the」が「マルチプライザ」と軽くなっている部分があります。また、「cross multiply」の「cross」は「クロス」ではなく「クロス」と短く発音されることが多いので、注意して聞きましょう。これらのリンキングやリダクションを覚えると、英語の発音を良くすることができます。

ネイティブのように話すコツ

スピーカーは説明を進める際、重要な用語やステップを強調して発音しています。例えば「first thing you can do」の「first」や「cross multiply」の「cross」は音量を上げ、長めに発音されています。このリズムとストレスを真似ることで、より自然な英語を話すことができます。shadowing siteを使って、動画の音声に合わせて繰り返し話す「shadow speech」の練習をすると効果的です。shadowspeakの技術を磨くことで、スピーキングの流れが格段に向上しますよ!

さあ、今すぐ動画を見ながら練習して、分数の足し算と英語のスキルを同時に上達させましょう!

この動画の文法

話し手がよく使っている文型を、動画の実際の表現とともに紹介します。

文型動画での表現
最上級 the -est / the most … — グループの中で一番the least common · the lowest
「might / may」による可能性 might/may + 動詞 — 起こりうるが確実ではないことmight find · might even be
「going to」の未来表現 be going to + 動詞 — 予定や、起こりそうだと分かることwe're going to talk · we're going to add · i'm going to post
義務:must / have to / need to 何かが必要であることを伝えるneed to add · need to write · need to multiply

シャドーイングとは?英語上達に効果的な理由

シャドーイング(Shadowing)は、もともとプロの通訳者養成プログラムで開発された言語学習法で、多言語習得者として知られるDr. Alexander Arguelles によって広く普及されました。方法はシンプルですが非常に効果的:ネイティブスピーカーの英語を聞きながら、1〜2秒の遅延で声に出してすぐに繰り返す——まるで「影(shadow)」のように話者を追いかけます。文法ドリルや受動的なリスニングと異なり、シャドーイングは脳と口の筋肉が同時にリアルタイムで英語を処理・再現することを強制します。研究により、発音精度、抑揚、リズム、連音、リスニング力、そして会話の流暢さが大幅に向上することが確認されています。IELTSスピーキング対策や自然な英語コミュニケーションを目指す方に特におすすめです。

シャドーイングのやり方: ステップ別の完全ガイドを読む →