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