WEBVTT
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Unit Fractions: Halves, Thirds, and Quarters
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In this video, we will learn how to write unit fractions representing halves, thirds, and quarters of shapes and describe what fraction of a shape is shaded.
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Which of these models show halves?
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How do we know what a half is?
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Let’s look closely at the models.
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Here’s a model of a square.
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The square has been divided into two parts.
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Does that mean that each part is a half?
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No, it doesn’t.
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Halves are equal parts.
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If we were to divide the square into two equal parts, each part would be a half.
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So the square has not been divided into halves.
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Has this triangle been divided into two equal parts?
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Yes, it has.
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We can call each part a half.
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This is how we write a half.
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This is one part out of two equal parts.
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Has this circle been divided into two halves?
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No, it’s been divided into two parts, but they’re not equal parts.
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So we can’t call the parts of the circle halves.
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How about this cube train?
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Has it been divided into two equal parts?
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There are six cubes altogether.
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Three of them are blue, and three of them are orange.
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Each part of the cube train is equal.
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Each part has three cubes.
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So we can call each part a half.
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So we’ve learned that a half is one of two equal parts.
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And we write it as a one over two, one out of two equal parts.
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So we can say that half of the triangle is shaded blue and half of the cube train is blue.
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One out of two equal parts are shaded.
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This rectangle has been divided into three equal parts.
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What do we call each of the parts?
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This is a third, and this is how we write it, one over three, one out of three equal parts.
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Has a third of this triangle been shaded pink?
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The triangle has been divided into three parts.
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But are they equal?
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No, they’re not.
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This triangle hasn’t been divided into thirds, just three parts.
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Has a third of this square been shaded green?
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Yes, it has.
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The square has been divided into three equal parts.
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All of the parts are the same size.
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And one out of those three parts has been shaded.
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What fraction of this circle has been shaded pink?
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The circle has been divided into four equal parts.
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When we divide a shape into four equal parts, we call each part a quarter or a fourth.
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And this is how we write it.
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Let’s recap what we’ve learned about fractions.
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If we divide a shape into two equal parts, we call each part a half.
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And this is how we write a half.
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A half is one out of two equal parts.
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When we divide a shape into three equal parts, we call each part a third.
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This is how we write a third.
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And a third is one out of three equal parts.
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And when we divide a shape into four equal parts, we call each part a quarter or a fourth.
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This is how we write it.
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A quarter is one out of four equal parts.
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Let’s try practicing what we’ve learned with some example questions.
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This rectangle is partitioned into equal parts.
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One out of what equal parts is shaded.
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Complete the fraction: What quarter of the area is shaded.
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This rectangle has been partitioned or divided into equal parts, and one of the parts has been shaded.
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In the first part of the question, we need to work out how many equal parts the rectangle has been partitioned or divided into.
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Did you count the number of equal parts?
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There are four.
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One out of four equal parts is shaded.
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And in the second part of the question, we need to write this as a fraction.
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One out of four equal parts is a quarter.
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The rectangle has been divided into four equal parts, and one of those parts or one-quarter is shaded.
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What fraction is shaded?
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We’re shown a picture of a rectangle.
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How many equal parts has it been divided into?
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There are two equal parts.
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We call each part a half.
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One of these halves has been shaded.
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The fraction of the shape which has been shaded is one-half.
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Consider the shape shown.
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One out of what equal parts is shaded.
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Pick the fraction that shows how much of the shape has been shaded.
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We’re told to consider, which means think about, the shape which is shown.
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We can see that one of these equal parts has been shaded.
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In the first part of the question, we need to think about how many equal parts there are altogether.
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There’s one, two, three equal parts.
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Each part is the same size.
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So we can say that one out of three equal parts is shaded.
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Now, we have to pick the fraction that shows how much of the shape is shaded.
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We know that one out of three equal parts have been shaded.
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How do we write this as a fraction?
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We know that this is not the correct fraction because this says that three out of one equal parts have been shaded.
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That’s not correct.
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The other three remaining fractions show that one out of some parts have been shaded.
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The first fraction is one out of three shaded parts or one-third.
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This must be the correct fraction because one out of three parts in our shape have been shaded.
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If one out of three equal parts is shaded, the fraction of the shape that has been shaded is one-third.
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What have we learned in this video?
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We’ve learned that halves, thirds, and quarters are equal parts of a whole shape.
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We’ve also learned that half is one out of two equal parts.
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A third is one out of three equal parts.
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And a quarter is one out of four equal parts.