Intro Quiz: Comparing 2-digit numbers

Video: Comparing 2-digit numbers

﻿Hello everybody and welcome to today's math session. My name is Miss Hughes, and today we're going to be looking further into our unit numbers within 100 and looking specifically at the objective, comparing two digit numbers. In this particular lesson, we are going to be looking at using signs more than, less than and equal to, to compare two digit numbers. For today's lesson, you are going to need a pencil and a rubber, some paper and you will also need some countable objects like my counters here to represent tens and ones. If you haven't got dienes or counters at home, you could use something like pasta, for example, although make sure you ask an adult at home before you go and get these things. If you don't think you have any countable objects at home, you can always draw out your tens and ones. Please pause the video now to go and get these things if you haven't got them already. Okay team, let's have a look at our lesson agenda for today to see our learning journey. We're going to start off by comparing the tens and ones in two digit numbers then we'll have a talk task. Next, we will be learning to use the less than, more than and equal to signs accurately and there will be an independent task focused on this. Finally, there will be a quiz at the end to check how much you have remembered at the end of the lesson. I wanted to start off our new learning today with a picture of a market stall that you can see here. Two customers came to the market store and bought different amounts of fruit, and we need to compare the amount of fruit each of them, each customer bought and these are shown on the slide here. To do this I'm first going to need to count the fruit. So let's start by counting this one here. 10, 20, 21, 22, 23, 24, 25. So this customer brought 25 pieces of fruit and this customer bought 10, 11, 12, 13 pieces of fruit. There we go. Now that we know how much fruit each customer has bought, we come back, present these numbers in a place value chart like this one. So the number 25, I know has two tens. So 10, 20 and five one's, 21, 22, 23, 24, 25. and number 13 has one 10. So there we go, that's 10 and there are three ones, 11, 12, 13. So now that I've presented my two numbers using dienes in our place value chart, I can start to compare them. Which number is greater and how do you know? I'm going to give you a few seconds to think about this question. See if you can explain to me using our place value charts, which number is greater and why? Okay, let's look at this altogether now. When comparing two digit numbers, we need to look at the tens first and then the ones. So let's have a look at our tens columns. In this number 25, I have two tens, which is equal to 20. Whereas in here I've only got one 10, which is equal to 10. So straight away, I can see that 25 is greater than 13. I know this because 25 has two tens, which is greater than one 10 that the number 13 has. When the number of tens is different like this, and we're comparing two numbers, we don't need to look at the ones columns because we can already tell which number is greater. Here that was 25. However, if the numbers of tens was the same, I would need to look at my ones to compare the numbers. If you had these two digit numbers now, so we have 36 and we have 32. Which is greatest? Let's start by representing our tens and ones in a place value chart. So the number 36, I know has three tens, 10, 20, 30, and six ones, 31, 32, 33, 34, 35, 36. And number 32 also has three tens, 10, 20, 30 and two one's 31, 32. So now that we have our two representations, which number do you think is greater? I'm going to give you a little bit of thinking time for this. See if you can explain to me using our place value charts, which number is greater and why? Great thinking team. Let's look through this together. Now, remember when we're comparing two digit numbers, we need to look at the tens first and then the ones. So let's have a look at our tens columns. I have three tens here in my number 36 and I also have three tens here in my number 32. Because the number of tens in both numbers is exactly the same, I can't figure out from my tens column which one is greater. So now we need to look into the one's column to see, to help us compare which number is greater. 36 has six ones, one, two, three, four, five, six, and 32 has one, two ones. Two is less than six, which means 32 is less than 36. 36 therefore is the greatest, has the greatest value. Let's do one last one. So we have the numbers 24 and 42 and I want to know which is greatest. So let's start by representing our tens and ones in a place value chart. The number 24 has two tens and four ones. Number 42 has four tens and two ones. And now that we have our two representations, we need to look at the tens column first and then the ones to compare them. So let's have a look at our tens column. I have two tens here, my number 24, and I have four tens here in my number 42. I can tell just from looking at the tens, which number is greater. So I do not need to look at my ones at all to compare my two numbers. 42 is clearly greater than 24, because four tens is greater than two tens. Team, it's that time already. We're now ready to move on to our talk task. So for this task, you're going to be given two sets of number cards like this pink set and blue set that I have here. And using those two sets of number cards, you are going to need to make the greatest numbers that you can with those cards and then you're going to compare those two numbers to find out which one is the greatest or has the greatest value. We're going to use place value charts to help us. So I've got them here and we'll also use some sentence structures to help our explanations. So I'll do this first one and then you are going to have a go at the next one. So I'm going to start by making the greatest number I can from my pink cards first and I'll flush the sentences up as I go. I have a five. That's the greater number out of all of my numbers in the card set. So I'm going to put it in the tens place. I have a three, that's the next greatest number. So I'm going to put it in the ones place. My number is 53. I'm going to make these out of dienes now so that I can see it represented really clearly. So I've got five tens. So I've got them here represented now in dienes, there we go, my five tens and three ones, brilliant. Now I am going to move on to my new cards, my blue ones. I have a six, that's the greater number here. So I have to put it in the tens place. My next greatest digit is four here. So that will go in my one's place. My number is 64. So now I'm going to represent that dienes. So I need six tens like this and four ones. Well, I can see even the number of tens that I have in my number 53 and 64, that 64 is the greater number. 64 is greater than 53 because it has six tens which is greater than five tens. Okay team, it's now your turn. So you are going to repeat the activity yourselves, but with these different number cards on this slide. So pause the video now and resume the video when you are ready to continue. Let's go through those answers then. So the greatest number you could have made with the pink cards was 96 and the greatest number that you could've made with the blue cards was 88. So in 96 you have nine tens, which is greater than eight tens so therefore 96 is the greater number out of these two numbers. Moving on to our develop learning for today, we're going to be learning to use signs for comparing our numbers now. So we've already looked at how to compare numbers and decide which number is greater and now we're going to be looking at using three signs, which mean less than, equal to and more than. So these are my three signs and we're going to think about how we can use them to show whether a number is greater than another number, is less than another number or is equal to another number. Let's see how these signs work by comparing some amount of apples on this slide. So here I have, sorry, I have two groups of apples, okay? So I've got one group of three apples here and I've got one group of three apples here. I have the same number of apples which means the amount of apples is equal. Therefore, to show that this group of apples is equal to this group, I need to use an equal sign like this. This means that three apples is equal to three apples. Let's look at another one. So here I have one apple on this side and five apples on another side. I know that one apple is less than five apples so I need to use the less than sign to show that. So here's my less than sign. This means that one apple is less than five apples. When I'm using the less than or more than sign, the smaller part of the sign always has to face the smaller number. So this small thin part of the sign is facing the one because that's the smaller number. The wider part of the sign always faces the larger number, the greater number. Let's look at one more. Here I have four apples and a group of three apples. I know that four apples is greater than three. So to show that four is more than three, I need to use my more than sign. It has to go this way because remember the larger part of my sign always faces towards the bigger number, which in this case is four and the smaller part of the sign always faces towards the smaller number which in this case is three. This means that four is more than three. Right team, we're now going to compare some two digit numbers and using our new signs to help us do this. So I've got my new signs up in the corner. Before I can compare them, I'm going to make sure that I make them with dienes in a place value chart so I can see really clearly what my numbers look like. So the first two numbers are 17 and 71. So that I can compare them accurately, I'm going to make them using dienes. You could do this with a bead string or any countable objects, but I'm going to use dienes in this instance. So 17 has one 10 and seven ones. So that's 10 and seven ones, 11, 12, 13, 14, 15, 16 to 17. So I've made my number 17 here. 71 has seven tens. There we go, 10, 20, 30, 40, 50, 60, 70 and one, one 71. Brilliant, now I can compare them. So I start by looking at the tens column first and I can see straight away that seven tens is greater than one 10. I don't need to look at my ones because I can already tell from my tens that 71 is the greater number. 71 is greater than 17, 17 is less than 71. Now remember when I'm using my signs, the smallest part always faces the smallest number and the larger wider part always faces the greater number. So I'm going to use this sign. This shows that 17 is less than 71. I can't use the equal sign here because they're not equal and if I was to use the more than sign, that would mean 17 is more than 71 which we know is incorrect. Let's move on to the next one. So our new numbers are 13 and 30. I'm going to start off by making my numbers in my place value chart here. So 13 has one ten and three ones and has 30 has three tens and no ones. Looking at my place value charts, I can tell immediately this 30 is the bigger number because I look at my tens column first and three is greater than one. So 30 is the greater number. I do not need to look at the ones columns because I can tell from my tens columns already, which number is greater. So to show that 13 is less than 30, I'm going to use the less than sign like this. Remember the sign that I use, the smaller part always has to be next to the small number and the wider part always goes near the larger number. What if I was to switch my 13 and 30 around like this? Does that mean that my sign will stay the same or will it need to change? I'll give you a few seconds thinking time to think about this. So you might have realised that we do need to change our sign because I've switched over my numbers 30 and 13, my sign has to change as well. This is because my greatest number is on the other side now and remember that the wider part of the sign always faces next to the bigger number or the greater number, but the sign this way round, it is saying that 30 is less than 13 and we know from our representations over here that that isn't true. So let's switch our sign now. There we go, perfect. Now it says 30 is greater than 13 and I know that my sign is the right way round because the wider part is facing the greater number. Let's look our last set of numbers now. So we have 35 and 35. 35 has three tens and five ones and 35 again has three tens and five ones. Remember when we're comparing two numbers, we need to look in the tens column first, but you'll notice that 35 here has three tens and in this number has three tens. So they have an equal number of tens. That means I can't tell you which number is bigger or which is greater. So I need to look at my ones now. Oh, they both have the same number of ones. They both have five ones. Because they have an equal number of tens and ones, I know that 35 and 35 are the same. In other words, they are equal to one another. So I can't use a more than sign or a less than sign because one is not more or less than the other. Instead, I need to use an equal sign like this. This shows that 35, 35 is equal to 35. Okay, now it's time for your independent task team. So using the four digit cards that you can see on the screen, you are going to make as many two digit numbers that you can. And then I would like you to compare them using the less than, more than and equals to signs. See if you can make as many combinations as you can of different numbers and comparing them to get this into practise. Pause the video now to complete your task and resume once you are finished. Welcome back team, great effort on that independent task. I'm now going to go through some example answers. There were so many different combinations that you could have had as you answer. So you might come across some of the ones that you came up with, but you've probably come up with lots of different ones to me as well. We'll just look through these ones for now. You can see that before I compared any of my numbers, I drew them out on a piece of paper in tens and ones so that I could compare them easily. Okay, the first combination that I have is 60 and 31. 60 has six tens, 30 has three tens so I know that 60 is more than 31. Let's write that in here. You could have had 10 and 36 and we know that 10 is less than 36 because 36 has three tens, but 10 only has one 10. 61 and 16, you could have had 61 is more than 16 and we know that because 61 has six tens and 16 has one 10. You could have had 63 and 63 and we know that they are equal to one another. They both have six tens and they both have three ones. So they're exactly the same. Really well done if you've got those combinations guys, although, like I said, there were many different combinations that you could have had. So well done if you found some other ones, that's fantastic work. That is the end of our lesson today team. Really well done on your hard work today with comparing two digit numbers and using our more than, less than and equals to signs. I'm looking forward to seeing you on another session. Goodbye. When the video ends, don't forget to complete your quiz to recap all of the learning that you did in today's lesson. If you'd like to, please ask your parent or carer to share your work on Instagram, Facebook or Twitter tagging @OakNational and #LearnwithOak.

Worksheet: Comparing 2-digit numbers

Exit Quiz: Comparing 2-digit numbers

Completed: Comparing 2-digit numbers

In this lesson we are going to be representing 2-digit numbers, comparing the tens and ones in 2-digit numbers and identifying which number is greater or less.

Maths

Comparing 2-digit numbers

Introductory Quiz

Video

Worksheet

Final Quiz

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