Lesson Video: Comparing Two-Digit Numbers: Models Mathematics • 1st Grade

Video Transcript

Comparing Two-Digit Numbers: Models

In this video, we will learn how to compare two-digit numbers using models.

Two-digit numbers have a tens digit and a ones digit. We can model two-digit numbers using ten frames and counters, an abacus, or place value blocks. And we can use a place value chart to think about what each digit is worth in a two-digit number. We can also use models and place value charts to help us compare two-digit numbers.

Our first two-digit number has two tens. So we can write a two in the tens place. And it has nine ones. This model shows the number 29. Two tens and nine ones makes 29. Our second model shows one ten and four ones. A 10 and four ones makes the number 14.

We can use the symbols less than, equal to, or greater than to compare our two numbers. Let’s start by comparing the tens. Our first number has two tens, and the second number only has one ten. So we can say 29 is greater than 14 because two tens are more than one ten.

Let’s practice comparing two-digit numbers using models.

Fill in the blank using greater than, less than, or equal to. Matthew’s set is what Noah’s set.

We’re shown two different models, Noah’s model and Matthew’s model. Both models show an amount of tens and ones. So we know that these are both two-digit numbers. How many tens are there in Noah’s model? One, two, three, four. Noah’s model has four tens. Now, let’s count how many ones his number has. One, two. Noah’s number has four tens and two ones. Four tens and two ones is 42. Noah’s number is 42.

Now, let’s look at Matthew’s number. How many tens does it have? There are three. One, two, three. Let’s count the number of ones. There’s one, two, three, four, five, six. Matthew’s number has three tens and six ones.

Now that we know what both two-digit numbers are, we can compare them. We need to compare the tens digit because this digit has the greatest value. Noah’s number has four tens. Matthew’s has three. And we know that four is more than three. So four tens, or 40, is worth more than three tens, or 30.

Now, we can fill in the blank. We have to compare Matthew’s set to Noah’s set. We know that three tens are less than four tens. The number 36 is less than the number 42. Matthew’s number is less than Noah’s number.

Emma thinks that the number in Group C is greater than the number in Group D. Is this true or false?

Let’s start by looking at the number in Group C. How many tens does this number have? It just has one ten. So we can write a one in the tens column. How many ones does this number have? One, two, three, four, five. So we can write a five in the ones column. The number in Group C is the number 15. One ten and five ones makes 15.

Now, let’s look at the number in Group D. How many tens does this number have? There are two tens. Now, let’s count the ones. One, two, three, four, five. Both numbers have five ones. The number in Group D is the number 25. Two tens and five ones makes 25.

Emma thinks that the number in Group C, which is 15, is greater than the number in Group D, which is 25. Is she correct? Is 15 greater than 25? One ten is less than two tens, so the number 15 is less than 25. Emma’s statement is false. 15 isn’t greater than 25. It’s less than 25. The correct answer is “false.”

Pick the symbol to compare these sets of ten frames. Is it less than, greater than, or equal to?

We’re shown two different models. We have to work out which number each model represents. And then we need to compare the numbers. How many tens does the first model have? Both of these ten frames are full. They both contain 10 counters. So there are two tens in our first number. And how many ones can you see left over? There are two. Two tens and two ones gives us the number 22.

Now, let’s look at our second number. There are three ten frames, and they are all full of counters. And there are no ones left over. Our second number is 30. Three tens are 30. 22 is less than 30. The number 22 has two tens, and the number 30 has three. And we know that two is less than three. The correct symbol to compare these two numbers is “less than” because 22 is less than 30.

What have we learned in this video? We’ve learned how to compare two-digit numbers using models.