Video Transcript
Comparing Groups by Matching
In this lesson, we’ll learn how to
compare two groups of up to 10 objects using a matching strategy. When we compare two groups of
objects, we usually say one of three things. We may say that one group contains
more than another group. We could say one group has less
than another group. Or if both groups are exactly the
same, we could say that one group is equal to another group. These are the sorts of words that
we’re going to be using. And these are the sorts of words
that help us to compare groups together.
Here’s a group of penguins and here
our group of eggs. Penguins, eggs, how can we compare
these two groups together? Is the number of penguins more
than, less than, or equal to the number of eggs? Well, because our objects are lined
up nicely and equally spaced, we can match them up together. One penguin can be matched with one
egg. Let’s do that and see what we have
left over at the end. One, two, three, four. Now, that’s all the eggs we
have. We can’t count five because we’ve
got nothing to match our last penguin to. So we can say that the number of
penguins is more than the number of eggs. This penguin’s egg has already
hatched.
We compared both groups by matching
the objects one by one. This is a good way of spotting
which group is the largest. Now, the trouble is with groups of
objects they don’t always come in nice, neat rows. What if a group of objects is
jumbled up? Here, we have two groups again, one
group of penguins and one group of eggs. But this time, they’re not lined up
neatly for us to match them. How could we compare the size of
each group now?
Well, we could still use lines to
match the groups. But it’s not always easy to spot
which group is larger this way. A clearer way to help us find the
answer is to use maths equipment. Let’s use cubes. We could start by putting an orange
cube next to each penguin. There we go. One cube represents one
penguin. Now, let’s move our cubes one by
one to make a line. We have one, two, three, four,
five, six cubes. This means we have six
penguins. And now, we can do the same with
the eggs. One cube to represent each egg. And now, let’s count them. One, two, three, four, five,
six. There are six cubes, which means we
must have six eggs.
Six was the number we counted too
when we counted the number of penguins. And if we look at our lines of
cubes, we can see that they’re both the same length. We know that both groups are the
same size. The number of penguins is equal to
the number of eggs. And again, we’ve used a matching
strategy to compare the groups together. Let’s practice our matching
strategy as we try some questions.
Charlotte and Mason are making
towers. Who has used the most cubes?
The question tells us that
Charlotte and Mason are making towers. And we can see those towers in the
picture underneath. There are two towers of cubes. And they’re labelled for us so we
can see whose tower belongs to who. Charlotte’s cubes are yellow, and
the green tower is made from Mason’s cubes. Our question asks us, who has used
the most cubes? This means we need to compare the
number of cubes in both towers. We can do this by matching the
cubes one at a time. Let’s count as we do this, one —
we’ve matched up another pair of cubes — two, three. What do we do now? We can’t match anymore. There are no more of Mason’s cubes
that we can match. He’s made a tower three cubes
tall.
But what about Charlotte? Let’s keep counting — remember, we
got to three — four, five, six. Charlotte has made a tower six
cubes tall. By matching the cubes one by one,
we found that the number of cubes that Charlotte used was more than the number that
Mason used. When we look at the towers, we can
see Charlotte’s tower, the yellow tower, is taller. And so, in answer to our question,
we can say Charlotte has used the most cubes.
Fill in the blank. The number of oranges is what the
number of strawberries.
This question is getting us to
compare a group of oranges with a group of strawberries that we can see in the
picture. So what could our possible answers
be? Well, the number of oranges could
be less than the number of strawberries. It could be more than the number of
strawberries. Or perhaps both groups are the same
and it’s equal to the number of strawberries. Now, we need to be careful when
we’re answering this question. Because we could look at both lines
of fruit and think they’re almost the same length. Perhaps that’s the same amount of
each type of fruit. But when we look closely at the
picture, we can see that, firstly, the oranges are larger than the strawberries. And, secondly, each piece of fruit
isn’t level with each other.
So if we’re going to use a matching
strategy, we need to be careful. Let’s match up each orange with a
strawberry. One, two, three. We’ve got no more oranges to match
up, but we still have a strawberry left over. This means there are more
strawberries than there are oranges. Well, if we say the other way
around, there are less oranges than there are strawberries. We’ve matched the pieces of fruit,
and we can now fill in the blank. The number of oranges is less than
the number of strawberries.
Are there more animals in group
A?
In this question, we can see two
groups of animals. These are labelled A and B. Now, we need to compare these two
groups together because we’re asked, are there more animals in group A? We can find out the answer by
matching the animals in group A with those in group B. Now, we can see just by looking at
each group that some of the animals are the same. But when we talk about matching
objects — in this case, we’re matching animals — we’re not talking about looking for
the same animals. We just need to count the number of
animals in each group. So it doesn’t matter that there’s a
duck in group A and there’s also one in group B. We just need to count the whole
group.
Now, to be able to match up these
animals together, it would be helpful if they were standing in a line one above
another. But, of course, we can see in the
picture that they’re not. Let’s use maths equipment to help
us here. We could start by putting a counter
next to each animal in group A, one counter for one animal. Each counter represents an
animal. Now, let’s do exactly the same with
group B, again one counter for one animal. Now, although we can’t move our
animals around, we can move our counters.
Let’s move one counter at a time
from each group. And we’re going to count as we do
so to see how many animals there are in each group and to be able to match up these
animals. One, two, three, four — can you see
what’s going to happen here? — five. We’ve matched up five pairs of
counters. But we can’t match up anymore. We’ve used all the counters in
group B. So we know there must be five
animals in group B. But we can see that there’s another
animal and another counter left in group A. There are not five but six animals
in group A. We can see that the line of
counters for group A is longer than the line for group B. So we can say group A is a larger
group than group B. Are there more animals in group
A? Yes, there are.
So what have we learned in this
video? Firstly, we’ve learned how to
compare groups of up to 10 objects. And the way we’ve done this is by
matching each object one by one. Secondly, we’ve used words like
more, less, and equal to help us describe the comparisons we’ve made.
