Video Transcript
Dividing into Equal Groups
In this video, we’re going to learn
how to divide a number of objects into equal groups. Now, what do we mean when we say
equal groups? We mean groups that are the same
size or groups that have the same amount. Here are three polar bears and a
pile of 12 fresh fish. Now, let’s imagine that they want
to share or divide these fish out between them. What if they split up the fish like
this? Is it fair? No, it’s not, is it? One bear has more fish than the
others. The groups of fish are not
equal. They don’t contain the same
amount.
One way that we can make sure that
we divide a number of objects into equal groups is to add the objects into groups
one at a time. Maybe you’ve divided some sweets
this way in the past: one for you, one for me, one for you, and so on. Let’s try dividing our 12 fish this
way. We’ll begin by adding one fish to
each polar-bears group. Now, they all have one fish. Now, let’s add another fish: one
for the first bear, one for the second bear, and one for the third bear. And we can keep splitting up the
fish like this until there are no fish left. Can you see? Now, each bear has the same amount
of fish. The groups are equal. We had 12 fish, and we divided them
into three equal groups. There are four fish in each
group. So our polar bears are finally
happy.
But what about the fish? Now, let’s imagine that underneath
the ice there are 12 fish swimming around. But they don’t much want to be
caught by a polar bear. And at the moment, they’re in one
big group. So they decide to split themselves
into groups of two to stay safe. How many groups of two will there
be?
We could draw rings around
them. Here’s one group of two, and
another, one more. Can you see that each of these
groups are the same size? They’re all equal. We have divided 12 fish into equal
groups of two. There are one, two, three, four,
five, six groups altogether.
Shall we put into practice what
we’ve learned now? Let’s try answering some questions
where we have to divide an amount into equal groups.
16 cookies are divided into groups
of what. There are what groups.
This question is about something
that happens in cookie factories all over the world every day, because we have an
amount of cookies that’s been divided into packets. We could call these packets groups
really. And they look like they’re equal
groups, don’t they? Equal groups are groups of the same
size. And when we’re talking about
packets of cookies, what we mean by equal groups is that you’re going to buy a
packet from the shop and it’s going to contain the same number of cookies as your
friend. Nobody is going to be
disappointed.
In the first sentence, we’re told
that we start off with 16 cookies. It tells us 16 cookies are divided
or split up or shared out. We could use 16 counters to
represent our 16 cookies. Now, in our first sentence, we’re
told that the 16 cookies are divided into groups of what. Let’s get cookie counting.
In the first packet or group, we
can see one, two, three, four, five, six, seven, eight. Now, for our two packets to be
equal, we’d expect to see eight cookies in the second group too. And we can count one, two, three,
four, five, six, seven, eight. Just like we thought, our groups
are the same size. Let’s split up our counters in the
same way. So if we split up 16 cookies into
groups of eight, how many groups will there be?
Our second sentence says there are
what groups. We split our counters into one, two
groups of eight. And we know that from the top
picture, don’t we? Because the cookies have been
divided into two packets or two groups. 16 cookies are divided into groups
of eight. There are two groups.
Look at the picture, and then
answer the questions. 15 books are divided into what
equal groups. There are what books in each
group.
This question starts off by telling
us to look at the picture. So, do you think we better do
that? What can you see? We can see some piles of books,
can’t we? There are one, two, three
piles. What else can we tell? How many books are there
altogether? Let’s count them. There are one, two, three, four,
five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15 books altogether. Can you see the number 15 in our
first sentence? We are told that 15 books are
divided into equal groups.
We’ll talk about the equal groups
in a moment. But to begin with, we need to find
out how many equal groups there are. Well, each group is a different
pile, isn’t it? As we’ve said already, there are
three piles of books. Our 15 books have been divided or
split up into three equal groups. What do we mean when we say that
some groups are equal? They’re groups of the same
size. So our 15 books have been split up
into three groups of the same size.
Can you imagine three children
going to the library and coming out with the same number of books each? Now, some of these books are
thicker than others, aren’t they? So maybe these piles don’t look the
same size. But in our final sentence, this is
what we need to find out. There are what books in each
group.
Let’s count them. In the first group, there are one,
two, three, four, five books in the first group. Now, if our groups are the same
size, we’d expect to see five books in the other two groups too. Well, we can see five books in the
second pile and five books in the third group. If we split 15 objects into three
equal groups, there will be five objects in each group. We know this because in the picture
15 books are divided into three equal groups. And there are five books in each
group.
How many groups of three apples are
there?
In this question, we’re shown an
amount of apples and we need to split it up or divide it into equal groups. And we know that it needs to be
split up into equal groups because we need to find out how many groups of three
apples are there. All of the groups we make need to
have three apples in them.
Now, if we look at the way that the
apples have been arranged, we can’t see any rows of three, can we? There aren’t really any groups of
three that jump out at us, which makes it quick to answer the question. So how are we going to count our
groups of three then? What if we circle them?
We can see one, two, three,
four. Can you see what we’re doing
here? We’re circling three apples every
time. We’re making equal groups. Five, six, seven, eight. We’ve divided this amount of apples
into equal groups with three apples in each group. There are eight groups
altogether.
David has 36 balls. He wants to divide them into groups
of 12. How many groups will he make?
In this question, we are told that
David has 36 balls. And we can see them in the picture,
can’t we? Here are David’s 36 balls. Now, we’re told that David wants to
divide these balls into groups of 12. Now, if each of the groups he makes
has got 12 balls in it, we can say that they’re going to be equal. They’re going to be the same
size. But how many groups is he going to
make?
Let’s use cubes to help us see how
many groups of 12 we can make. Our first group needs to have one,
two, three, four, five, six, seven, eight, nine, 10, 11, 12. That’s one group of 12 we’ve
made. But this is interesting; we’ve used
all the blue balls in the first section. Can you see how there’s a group of
blue, then a group of green, then another group of blue? It’s almost as if the groups are
being shown to us before we start.
But maybe they’re not equal groups
of 12. We can’t just look at the colors of
these balls. We’re going to have to carry on
counting to find the answer. On to the green balls, and we need
to make another group of 12. Let’s skip count in twos this time
to get there more quickly. Two, four, six, eight, 10, 12. They were 12 green balls. So do you think this last group of
blue balls might have 12 in it too? Should we try some even more speedy
counting? Let’s skip count in threes this
time. Three, six, nine, 12. We didn’t know for sure, but the
colors of the balls were giving us a clue all along.
David has 36 balls. And in the picture, we’ve counted
12 blue balls, then 12 green balls, then another 12 blue balls. So when David divides or splits up
his 36 balls into equal groups of 12, how many groups is he going to make? We know he’s going to make three
equal groups.
What have we learned in this
video? We’ve learned how to divide a
number of objects into equal groups.
