Lesson video

Hello everybody, my name is Miss Hughes and welcome to today's math session.

Today our objective is going to be exploring odd and even numbers as we look further into our unit numbers within 100.

So let's get started.

For today's lesson, you're going to need a pencil and rubber, some paper and also some countable objects that you can use to represent tens and ones.

So pause this video now to get the equipment that you need if you have not got these things already.

Our lesson agenda for today's session looks a little bit like this.

We're going to start off by exploring odd and even numbers as part of our new learning.

Then we're going to have a go on making some two digit numbers and identifying whether they're odd and even.

You will then have an independent task and of course at the end today's session, you will have a quiz where you can recap everything you've learned.

We're going to start off today's lesson by looking at these two number cards that I have picked at random.

So let's see what we've got.

We've got the number four and we've got the number six.

Okay, these are my two cards.

And I want to have a think about this question now, what two digit numbers can I make with these two digit cards? I'm going to give you a few seconds to think about it.

Have you come up with an answer? Brilliant, Let's have a look at the ones that I've come up with.

So if I've got my digit four and my digit six, I know that I can make the number 46 with four tens and six ones and the number 64 with six tens and four ones.

Now that I've made my two numbers with these two digit cards and these are the only two numbers that I can make out of my digit cards.

I want to think about which digit is the greatest.

So I'm going to give you a few seconds down to decide what number you think is the greatest out of 46 and 64 and why.

Okay, let's look at these two numbers a little bit closer.

To decide which one is greater, I'm going to make them both out of dean's so that I can compare them really easily.

So 46 has four tens so I've got my four tens here 10, 20, 30, 40 and six ones 41, 42, 43, 44, 45, 46.

The number 64 has six tens so I've got them here.

10, 20, 30, 40, 50, 60 and four ones 61, 62, 63, 64.

Okay, so I've made them both out of Dean's.

I can see that the greatest number therefore is 64 because it has six tens which is greater than four tens that 46 has.

I do not need to look at my ones column to the 46, or my ones column for 64.

Because I can tell already from my tens columns which number is the greater one and that is 64.

We're going to have a think now about what odd and even numbers we can make with these two digit cards.

Remember that the only two digit numbers that we could make with these digit cards were 46 and 64.

So we're going to look at these two numbers now and decide whether they are odd or even.

When we are deciding if a number is odd or even, we always have to look at the ones digit.

This this column is going to tell me whether my number is odd or if it is even if we look at number 46 first in the ones column, it has six ones, Six is exactly divisible by two.

I know that I can split the number in half like this.

And in either half, I have an equal number.

So I've got three on this side and three on this one.

So we know because this number six is divisible by two exactly that this whole number therefore is even.

Let's look at the number 64 now, there are four ones here, my ones column.

Remember, I'm not looking at my tens, I only look at my ones column to identify if a number is odd or even.

If I split it in half like this and put a line halfway between my ones, I can see that each half is equal.

I left with two on either side, two here and two here.

Therefore, the digit four in the ones column is divisible exactly by two, which means that this whole number 64 is also even If my ones number is not exactly divisible by two, then that would tell me the whole number would be odd.

As part of our Developed Learning today, we are going to have four single digit cards now that I'm going to pick at random, and we are going to try and find all of the different combinations of two digit numbers, we can with those four cards, so let's pick them out Two, four, one and five, okay, so here are my four digit cards.

And we are trying to find out how many two digit numbers we can make with these cards.

So to do this, I'm going to use place value charts to record all of the numbers I have made.

I'm going to start off with the digit one so I can make sure that I've made all of the combinations with one in the tens column and then I'll move on to two, four and five.

It's important that I do it this way so that I do not miss a potential combination of two digit numbers.

So let's start by putting one in the tens column.

If I've got my one there then I can see I can either have two, four or five in my ones column.

So let's put two in there.

Great.

Let's try another number with one in the tens column.

Okay, I've already put two in the ones column.

So now I'm left with the options of four and five.

So let's put four in the ones column next.

Brilliant, I can see that I still can have the number one in the tens column and have a new number in the ones column, so I can put five there.

Now I've made all of the possible combinations of numbers with one in the tens column and the other numbers in the ones column.

Let's move on now and put two in the tens column and see what numbers we can make with that digit.

If I've got two in there , if I've two in the tens column, I have the option of putting my digit one, four or five in the ones column.

So let's start with one just cause it's in the right order.

So I've got the number 21.

Now if I put the number two in the tens column again, I can put the number four in my ones Column cause I haven't got that option before.

And I can put the two in the tens column again, and I still got a five that I can put in the ones column.

So those are all of the combinations of two digit numbers I can have with the two that's in the tens column.

Let's have a look at all of the combinations I can have with four in the tens column now, so I can have four and one, four and two, and four and five.

Now let's have a look at the last set with five in the tens column.

Five and one, five and two, and five and four.

Now I have all of the possible combinations of two digit numbers using these four digit cards.

Let's read all of these two digit numbers that we've made.

So we've got 12, 14, 15, 21, 24, 25, 41, 42, 45, 51,52, 54.

We all have those combinations of numbers now it's going to be really easy to find these questions.

So I want to find the greatest even number that I could make using those four digit cards.

The greatest odds number that I could make using those four digit cards, the smallest even number I could make using those digit cards, and the smallest odd number I could make okay, because I've got all of my combinations here, it's going to be really easy for me to see which one is the greatest even number, the greatest odd number, the smallest even number and the smallest odd number.

Let's start by trying to find the greatest even number.

So I know that the greatest number that there is out of all of these numbers is the number 54 54 is the greatest because it has five tens which is the largest number of tens out of all of these numbers.

And even though all of these numbers here have five tens it's also got the most number of ones.

So it's got five tens and four ones, which is greater than five tens and two ones, and five tens and one one.

So this is my greatest number.

I'm going to represent this greatest number in deans now so I can see if it is odd or if it is even because remember we're looking for the greatest even number right now.

So we know this is the greatest and we need to see if it's odd or even now.

So this is what 54 would look like in dean's.

So I've got my five tens and my four ones.

Remember when we're looking if a number is odd or even, we need to look at the ones column which is here.

So I've got four ones and I can see that four is divisible exactly by two.

If I was to split these dean's in half, I would have two on this side and two on this side so equal halves.

So I know therefore that 54 is an even number.

And 54 is the greatest even number that I could make.

What is the greatest odd number we can make? Hmm, well I can tell that 51 is going to be the greatest odd number that we have.

This is how I would represent 51 in deans.

So I've got my five tens 10, 20, 30, 40, 50 and one, one.

I can tell that because 51 and 52 both have five tens.

They are the greatest numbers left.

However, 52 is even because two can be equally split into two.

51 on the other hand only has one, one and that cannot be split exactly by two, therefore 51 is an odd number.

So this is the greatest odd number that we have.

Now we are looking for the smallest even number that we can make.

So I know it's going to be one of these numbers over here, because these are my smallest numbers of all of the combinations.

I know that these are the smallest numbers because they've only got one ten in the tens column, whereas these numbers have two tens, these numbers have four tens, and these numbers have five tens.

So these numbers are all greater than this set of numbers over here 12 is the smallest number all together.

So let's have a look at that one first.

This is where it presented in, this is 12 represented in dean's, okay, so as in dean's 12 has one ten and two ones that's 10, 11, 12.

I can tell that this is an even number This is because in the ones column I have two dean's.

So if I was to split that by two or split that into two halves, I'm going to have an equal amount of dean's on either side of my half, Okay? So therefore because this number or two ones is equally divisible by two, I know that this whole number 12 is an even number.

Therefore, it is the smallest even number on this slide.

The smallest odd number can't be 14.

I know this because four is divisible exactly by two.

So let's have a look at the next smallest number 15.

The digit five which is in the ones column, is not divisible by two.

And I know this because if I was to represent 15 in Dean's like this, I cannot equally split these five ones into two I cannot do that exactly.

So therefore, this whole number is going to be odd.

And 15 is therefore the smallest odd number that we can make.

You are now going to have a go at this task yourself, rather than four digit cards now though you have nine digit cards.

And first, I want you to make as many two digit numbers that you possibly can with these numbers.

See if you can find all of the possible combination of two digit numbers using these using these cards.

Think about doing it in a systematic way like I showed you putting the same number in the tens until you found all of those combinations and doing it that way.

Once you've completed that task and found all of the possible two digit numbers that you can, I want you to find the numbers that match the statements.

So I want you to find the greatest even number you can make, the greatest odd number you can make, the smallest even number you can make, and the smallest odd number that you can make.

I would like you to represent those numbers in tens and ones, so you will need countable objects for this task.

If you do not have any countable objects however, like dean's, you can draw these pause the video now to complete your task and resume the video once you're finished and ready to continue.

Right team let's look through those answers.

So on the board you can see I have a number of two digit numbers.

And these are all of the possible combinations that you could have made using these nine cards.

You can pause the video here to see all of the ones that you got.

I'm not going to go through all of them on this video.

Then will be here for hours and hours.

So pause the video if you want to check your answers and play the video when you're ready to move on.

Okay, so let's move on to those statements then, if you had found all of those combinations of numbers, the greatest even number you could have made would have been 98 with nine tens And I know that it's even because we've got an eight in the ones column and if I divide eight by two, I get four okay, so that's divisible exactly by two, and therefore it is an even number.

The greatest odd number you could have had was 97.

The smallest even number you could have made was 10.

And the smallest odd number you can make is or was 13.

Well done if you managed to get those and also well done if you managed to get any of those combinations.

All that's left to do now guys is to complete the quiz.

So when the video is ended, Make sure you go and do your quiz to recap everything you've learnt in this session, and to show off all of your fantastic learning from today.

Team well done another fantastic lesson today You worked so hard on finding all of those two digit number combinations, and I was really impressed with how you identified odd and even numbers today.

I look forward to seeing you on another session very soon.

Bye bye.

If you'd like to please ask your parent or carer to share your work on Twitter tagging @OakNational and #LearnwithOak.