Video: Comparing Groups by Matching

In this video, we will learn how to compare two groups of up to 10 objects using a matching strategy.

09:59

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.

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