Video Transcript
Nonunit Fractions
In this video, we will learn how to
model and write nonunit fractions and describe the numbers in the fraction with the
words numerator and denominator.
Each of these bar models shows a
different fraction. Each of our three bar models have
been divided into equal parts. How many equal parts? Let’s count, one, two, three. When we divide a shape into three
equal parts, we call each of the parts a third. One of the thirds in this bar model
has been shaded orange. So we would say the fraction of
this shape which has been shaded is one-third.
How do we write one-third? First, we can write the
denominator. This is the number at the bottom of
the fraction. The denominator is the number of
equal parts, and the numerator or the number at the top of the fraction is a
one. This is the number of parts which
have been shaded. Two-thirds of our second shape have
been shaded, so the denominator is the same. There are still three equal
parts. But this fraction has a different
numerator because the number of parts which have been shaded is two. If the numerator in a fraction is a
one, we call this a unit fraction. The unit means one out of all the
equal parts, and nonunit fractions have a numerator greater than one like
two-thirds. In this video, we’re learning all
about nonunit fractions. Three-thirds of this bar model have
been shaded. Three-thirds is equal to the whole
amount.
What fraction of these bar models
have been shaded? How many equal parts do each of
these bar models have? One, two, three, four, five. When we divide a shape into five
equal parts, we call each part a fifth. Because we know that each of these
models has been divided into fifths, we know they all have the same denominator. This is the number at the bottom of
the fraction. The denominator is the number of
equal parts we’ve divided our shape into.
Now we just need to write the
numerators or the top number on the fraction. The numerator is the number of
parts we’ve shaded. The first fraction has two parts
out of five equal parts shaded. So we would write this as
two-fifths. Three-fifths of our second shape
have been shaded and four-fifths of our third shape. When the numerator or the top
number in the fraction is greater than one, we call these nonunit fractions.
This is a nonunit fraction. What fraction of this shape has
been shaded? There are three equal parts, so
each part is a third. Two of our equal parts are shaded,
so two-thirds of this shape is shaded. How do we write this as a
fraction? The bottom number of the fraction
or the denominator tells us the number of equal parts, and in this case there are
three. And the numerator or the number on
top of the faction tells us how many of our equal parts have been shaded,
two-thirds. Let’s practice what we’ve learned
about nonunit fractions by answering some questions now.
What fraction is shaded?
In this question, we have to write
what fraction of the circle has been shaded. Let’s start by thinking about the
denominator or the number on the bottom of the fraction. The denominator is the number of
equal parts our circle has been divided into: one, two, three, four, five, six. When we divide a shape into six
equal parts, we call each part a sixth. Now we can write the numerator or
the top number of our fraction. The numerator is the number of
parts which have been shaded. Five out of six equal parts have
been shaded or five-sixths. The fraction of the shape which is
shaded is five-sixths.
What fraction is shaded?
In this question, we’re given a
shape. Some of the shape has been shaded
green. We have to write this as a
fraction. First, we need to think about the
denominator. This is the number that we write at
the bottom of the faction. The denominator is the number of
equal parts that our shape has been divided into: one, two, three, four, five. When we divide a shape into five
equal parts, we call each part a fifth. Now we just need to write the
numerator or the number of parts which have been shaded. Two out of the five equal parts are
green, so two-fifths of the shape is shaded.
Jackson has shaded part of this
whole. Fill in the blank: what parts out
of five are shaded. What fraction is shaded?
In this question, we’re shown a
model and we can see that Jackson has shaded part of the whole. In the first part of the question,
we have to write the number of parts out of the five equal parts Jackson has
shaded. We know the whole amount shows five
equal parts. Jackson has shaded three of them
orange, so we can say that three parts out of five are shaded.
In the second part of the question,
we have to write this as a fraction. The bottom number in a fraction is
called the denominator. This tells us the number of equal
parts our shape has been divided into. We know there are five equal
parts. And when we divide a shape into
five equal parts, we call each part a fifth. And we know the numerator or the
number on top is a three because Jackson has shaded three out of the five equal
parts. So the missing number is three. Three parts out of five are
shaded. Three out of five equal parts is
equal to three-fifths.
Emma has shaded part of this
whole. Fill in the blanks: what out of
what equal parts are shaded. What fraction is shaded?
In this question, we’re told that
Emma has shaded part of this whole. The whole means the whole
shape. In the first part of the question,
we have to fill in the missing numbers. And we have to write the number of
parts which are shaded out of the number of equal parts altogether. Did you count the number of shaded
parts? There are four. Four parts of this shape have been
shaded blue. How many equal parts has this shape
been divided into? Let’s just keep on counting. We counted the four shaded
parts. Here’s another part; that makes
five, six. Four out of six equal parts are
shaded.
How do we write this as a
fraction? The numerator or the number on the
top is the number of shaded parts. And the number on the bottom or the
denominator tells us how many equal parts there are. When we divide a shape into six
equal parts, we call each part a sixth, so the fraction of the shape that is shaded
is four-sixths.
Write a fraction that has two as
the numerator and five as the denominator.
When we write fractions, the number
on the bottom is called the denominator. This tells us the number of equal
parts that the shape or the number has been divided into. And we’re told that the denominator
in this fraction is a five. When we divide a shape into five
equal parts, we call each part a fifth. Now that we’ve written the
denominator in our fraction, we just need to write the top number, the
numerator. We’re told that our faction has a
two as the numerator. We could model this by shading two
of our five equal parts. If a fraction has two as the
numerator and five as the denominator, then the fraction is two-fifths.
What have we learned in this
video? We have learned how to model and
write nonunit fractions. We have also learned to describe
fractions using the words denominator and numerator.