Comparing Two-Digit Numbers: Place Value
In this video, we will learn how to compare numbers up to 100 by comparing the number of tens and ones. Two-digit numbers have a tens digit and a ones digit. This number has one 10. We’ve grouped the 10 ones together into a tower. This is called a 10. And our number has six ones. 10 and six make 16. The tens digit in the number 16 is the one. The one is worth one 10. And the six digit in the number 16 is worth six ones. One 10 and six ones makes the number 16. Let’s try some practice questions. By looking closely at the tens and ones digits, we can compare the value of two or more numbers.
Mason has written 31 and 39 in a place value table. Does 39 have more, less, or the same number of 10s as 31? Does 39 have more or less ones than 31? Pick the smaller number. 31 or 39?
In this question, Mason is comparing two numbers. They are the numbers 31 and 39. They’re both two-digit numbers. In the first part of the question, we need to compare the amount of tens in both numbers. And in the second part of the question, we need to compare the amount of ones in both numbers. Let’s start by looking at the tens digit. This is in the column called tens. We can see that the number 31 has three 10s and the number 39 also has three 10s. So we can say that 39 has the same number of 10s as 31.
Now, we need to compare the amount of ones in each number. We can see that the number 31 has one in the ones place and the nine in 39 is worth nine ones. Nine is more than one. So we can say that 39 has more ones than 31. So which is the smaller number, 31 or 39? It’s number 31. Both numbers have three 10s. But number 31 only has a one in the ones place. 39 has nine ones. And we know that nine is more than one. So number 39 has the same number of 10s as 31, and 39 has more ones than number 31. The smaller number is number 31.
Which is greater, 97 or 77?
In this question, we’re being asked to compare two two-digit numbers. We can use place value tables to help us compare these two numbers. The number 97 has nine 10s and seven ones. And the number 77 has seven 10s and seven ones. Let’s start by comparing the ones digit. Both numbers have seven ones. 97 and 77 both have seven ones. Let’s compare the tens digit. Let’s compare the tens digits now. 97 has nine 10s. 10, 20, 30, 40, 50, 60, 70, 80, 90. Nine 10s makes 90. And the number 77 has seven 10s. 10, 20, 30, 40, 50, 60, 70. Which of our two-digit numbers has the most 10s? The number 97. It has nine 10s. And 77 only has seven 10s. So number 97 is greater than 77.
Hannah made three numbers with place value cards. 20 plus eight is 28, 50 plus two is 52, and 50 plus seven is 57. Pick the correct number sentences. Remember, to compare 28 and 52, we compare the tens digit. Is 28 equal to 52, less than 52, or greater than 52? 57 and 52 have the same tens digit. Compare the ones digit to find the correct number sentence. 57 is less than 52, equal to 52, or greater than 52. Which is the greatest number that she made?
This is a three-part question. In the first part of the question, we need to compare the numbers 28 and 52. We’re told how to do this. By comparing the tens digits. And if we look closely at the place value cards, we can see that 28 has two 10s and 52 has five 10s. We know that five is more than two, so 52 must be greater than 28 because 50, or five 10s, is greater than 20 which is two 10s. So 28 is less than 52.
In the second part of the question, we have to compare the numbers 57 and 52. And we’re told to do this by comparing the ones digit. This is because 57 and 52 both have the same number of 10s. They both have five 10s. Let’s compare the ones. 52 has two ones. 57 has seven ones. And we know that seven is greater than two, so we can say that 57 is greater than 52. So which is the greatest number that Hannah made? It’s the number 57. 57 has five 10s and seven ones; 28 only has two 10s. And although 52 has five 10s, it only has two ones. 57 has the most 10s and ones.
What have we learned in this video? We’ve learned how to compare two-digit numbers by comparing the number of 10s and ones.