# Lesson Video: Hundreds Mathematics • 2nd Grade

In this video, we will learn how to define a hundred as 10 tens or 100 ones, model 100 with place value blocks, and count in hundreds to 1000.

14:01

### Video Transcript

Hundreds

In this video, we’re going to learn how to describe 100 as 10 10s and 100 ones. We’re also going to learn how to model 100 using place value blocks and to count in hundreds all the way to 1000.

Let’s start at the very beginning. When we very first learn to count, we’re only thinking about small numbers. And so we learn to count in ones, don’t we? One, two, three, four, five, six, seven, eight, nine. But when we get to 10 ones, we start calling this one 10. If we squash down our 10 ones, they look the same as one 10, don’t they? Thinking of this amount as one 10 is an easier way of helping us understand numbers. And it’s a building block we can use to make bigger and bigger numbers. 10, 20, 30, 40, 50, 60, 70, 80, 90.

But what happens when we get to 10 10s? Is there an easier way we could model this number? What if we push all our 10 10s next to each other? We get a square block like this. 10 10s are the same as 100. And because we know there are 10 ones in every 10, we know 100 ones are also equal to 100. We could show this by counting all the little cubes that go together to make our hundred block. And we’d find that’d be 100 of them.

Now that we know what 100 looks like and what it means, let’s try counting in hundreds. 100, 200, 300, 400, 500, 600, 700, 800, 900. But what happens when we get to 10 100s? Do we just call this number 10 hundred? Well, just like we’ve learned in this video, when we get to 10 ones, they make a new building block and we give them a new name, one 10. And when we get to 10 10s, they make a new building block and we give them a new name, 100. And so when we get to 10 100s, it’s no different. We put them together to make a new type of number, which we can use to build bigger and bigger numbers. 10 100s are the same as 1000. And so we count 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000.

Let’s try answering some questions now where we have to practice modeling, reading, and also counting in hundreds.

This place value block is 100. How can we show 300?

In this question, we’re introduced to a place value block. We already know what ones and tens blocks look like. We’re told that this blue block is worth 100. And we can see this because it’s the same as just pushing 10 tens blocks together. 10 10s are the same as 100 ⁠— 10, 20, 30, 40, 50, 60, 70, 80, 90, 100. Now to show 100, we just skip counted in tens. But our question asks us to show 300. So we’re going to need to skip count in hundreds ⁠— 100, 200, 300. We know that one blue place value block is worth 100. And so to show the number 300, we need to use three of these hundreds place value blocks. Three 100s are the same as the number 300.

Look at the model. Daniel composed a three-digit number using bundles of 10 10s. What number did he make?

We’re told that Daniel has shown a three-digit number here. Let’s begin by looking at the model like we’re told to. There are lots of bundles we need to think about. Let’s zoom in on one of these bundles and see what it looks like. We can see that it’s a bundle of sticks, can’t we? And it contains one, two, three, four, five, six, seven, eight, nine, 10 sticks. And we know that 10 ones are the same as one 10. And when we group numbers into tens, they’re easier to count. Tens are like a building block where we can use to make bigger and bigger numbers.

But Daniel hasn’t just grouped 10 sticks together. He’s grouped his groups of 10 together, hasn’t he? And we can see underneath each group that he has 10 10s. Now what are 10 10s the same as? Let’s count each tens bundle until we get to 10 10s. One 10 is worth 10. Two 10s are 20. Three 10s are 30. Four 10s are 40. Five 10s are 50. Six 10s are the same as 60. Seven 10s are 70. Eight 10s are 80. Nine 10s are 90. Don’t get caught out here, though. 10 10s aren’t ten-ty. We say they’re 100. Daniel has grouped together his sticks in hundreds. And by doing this, he makes them even easier to count.

Hundreds are another building block that we can use to make bigger and bigger numbers. So we don’t need to count each individual stick. That will take a really long time, wouldn’t it? And we don’t even need to count in tens for each bundle. That will take quite a long time. Instead, we just need to count in hundreds for each group of 10 10s ⁠— 100, 200, 300, 400. By modeling the number like this, Daniel’s made it much easier to count.

We know we can write the number 100 by writing the digit 1, followed by two zeros. So because we need to write the number 400, we write the digit 4, followed by two zeros. Daniel’s taken bundles of 10 sticks and put them together to make larger bundles of 10 10s. And because we know that 10 10s are the same as 100, we can count quickly to find out the three-digit number that he’s showing. Four groups of 10 10s means four 100s, and so the number that Daniel is showing is 400.

Each jar contains 100 candies. Count in hundreds to find how many candies there are. Write the answer in digits.

In the first picture, we can see a jar of candies. And the first sentence tells us how many candies there are in it. Each jar contains 100 candies. Can you see how we write the number 100? It’s a one followed by two zeros. And we can see in the picture what 100 candies look like. Does this shape remind you of anything? Well, it might remind you of the 10 rows of 10 squares that we use to make a hundred square. And the place value block that we use to represent 100 looks like this too. Arranging the candies like this is a good way of helping us to remember that there are 100 in each jar.

Now we’re given a few jars of candies. We need to find out how many candies there are altogether by counting in hundreds. Now, imagine for a moment you were given all these jars of candies and somebody said to you, “right, I want to know how many candies there are altogether. Tip them all on the table and start counting, one, two, three, and so on.“ You’d have a huge pile of sweets and it will take you ages. Thankfully, our candies are arranged in groups or jars of 100. And this is going to make it much quicker for us to count.

Do you want to say each number as we point to the jar? 100, 200, 300, 400, 500. There are six jars of 100 candies, so we can count in hundreds six times to find out how many there are. There are 600 candies altogether. Now we’re told we need to write the answer in digits. Do you remember what we said at the start about writing 100 in digits? 100 is the digit 1 followed by two zeros. And we can see we’ve already got 100, 200, and 300 labeled already. 400 must be a four followed by two zeros. 500 is five, zero, zero. And so we know the number we want to write, which is 600, must be a six followed by two zeros. Six jars of 100 candies makes 600 candies altogether.

Each box contains 100 paperclips. Count in hundreds to find how many there are. Write the number in words. And write the number in digits.

We’re told that each of these boxes contains 100 paperclips. Now can you picture what 100 paperclips might look like? Well, this is 100 ones cubes. These are the same as 100, but we haven’t just got one box of paperclips, have we? We have one, two, three, four, five, six, seven, eight. So the number of paperclips altogether looks more like this. Now, imagine having to count each individual cube to count in ones to find the answer. This will be a very long video, wouldn’t it? But because our paperclips have been grouped together in hundreds, we can count in hundreds.

That’s better. Now we can do what the question asks us to do, which is to count in hundreds to find how many there are. Ready? 100, 200, 300, 400, 500, 600, 700, 800. Eight boxes of 100 paperclips is 800 altogether. First, we need to write our answer in words. So we begin by writing the number eight. That’s just the same as the number after seven, E-I-G-H-T. And then we just write the word hundred, eight hundred.

And finally, we need to write our answer in digits. We know that 100 is a one followed by two zeros, so the number 800 is simply the digit 8 followed by two zeros. There are eight boxes, and each box we know contains 100 paperclips. So we could find the total number of paperclips by simply skip counting in hundreds eight times. And we can write our answer in words and digits. That’s eight hundred or 800.

What’ve we learned in this video? We’ve learned how to describe 100 as 10 10s or 100 ones. We’ve also learned how to model 100 using place value blocks and to count in hundreds all the way to 1000.