To find double and half of an amount of money

Key Stage 1

Maths

Multiplication and division

﻿Hello again, my wonderful mathematicians. It's me Ms. Charlton back for another week of some wonderful learning. Of course I have my talk partner Headwig with me, hopefully you've got your talk partner with you as well. Now, has everybody had a restful weekend? I hope so. How are you feeling today? Maybe you are feeling energised and full of energy and excited. Maybe you're feeling a bit creative or quite calm or a bit sluggish. Sometimes after a weekend, we can feel a bit like a slug, a bit tired, but hopefully by the end of this lesson, you will feel energised. Now last week we we're learning all about money. And this week is very exciting. We are going to start a new unit. Our new unit is all about multiplication and division. And today you are going to be using all of your knowledge about money to find double and half of an amount of money. The topic of multiplication and division, and as always, you are going to need some paper and a pencil. And there are times when you will need to pause the video and have a go at some of the activities yourself. So, first of all, we're going to check our key vocabulary. Then you are going to need to use your knowledge of money to help you understand doubling. Then you're going to explore having in the context of money. And then you're going to do an independent task, two independent tasks today, actually, and check your answers. So let's start off with our star words, are you ready? Hands up, star words. Let's punch these out. Double. Half. Halve. Equal parts. Whole. Really well done. I wonder how many times you'll use those words throughout this lesson. We've got our brain teaser to warm up our brains. We need to read the equations in their colour pairs and figure out the missing numbers. Now I wonder if you can be a bit of a detective and spot the patterns in these number paths. So that first one there in purple. If I know that one plus one is equal to two, then I know that 10 plus 10 is equal to 20. Let's use that sentence to help us explain equation two. Two plus two is equal to four, 20 plus 20 is equal to 40. Can you see the pattern there? Let's check the next one. If I know that three plus three is equal to six, then I know that 30 plus 30, well done, is equal to 60. Do you think you can try the two equations at the bottom by yourself? Pause the video now and have a go. How did we get on? Four plus four is equal to eight, so 40 plus 40 is equal to 80. If I know that five plus five is equal to 10, then I know that 50 plus 50 is equal to 100. Wow, did you spot the patterns? It's just a different place value. The second equation all has the tens in them. That's like mathematical magic. Now I think we are all ready to get started with the lesson and children we are back at the Sunday market. Look, can you see all of our friends there shopping again. Now, today we are going to be focusing on the pig. Can you see the pig in the corner? Can you point to him for me? Now, he always comes to the market and he buys some bricks. Normally he buys one pack of bricks that cost five pounds, but today he needs double the amount of bricks. Maybe he's building a bigger house out of bricks. So if he needs double the amount of bricks, I wonder what double means. Can you have that whole think, and see if you can chat to your talk partner and explain what you think double means. Double means two equal amounts added together. Can you say that? Double means two equal amounts added together. Really well, done. So here we've got one amount of five pounds. So it's not just one lot of five pounds, but two lots. Double means two equal amounts added together. Because normally the pig just wants one pack of bricks that cost him five pounds, but today he wants two packs. So he's going to need five pounds for one pack of bricks and five pounds for the other pack of bricks. So now we know that we need to add them together. Let's have a look here at our whole part model. I've got my two packs of bricks in the parts. Look, can you see that they're the same in each one? And both of those, each of them cost five pounds. So there's five pounds and five pounds. I know from my number bonds, that five plus five is equal to, can you shout it out at me? Five plus five is equal to? 10. That's right. Five plus five is equal to 10. I have two equal parts added together to find the whole. Let's look carefully at representation's. I've got a whole part model, I've got cubes ,and I've got two different lots of beads strings. So let's look carefully. I want to know which of these representations show double seven, and which do not. There's a bit of a trick here. So look very carefully. I want you to count carefully the different parts that you can see, and I want you to see which ones show double seven and which do not. Pause the video now and a have a go, and then we'll check together. How did we get on? So I can see that the first whole part model, it does show double seven. Because, look at the chocolates in each of the parts. I can see one, two, three, four, five, six, seven, that's one part. And one, two, three, four, five, six, seven. Both parts are equal. Ah, remember that. Both parts must be equal. Seven plus seven is equal to 14. The whole is 14, the parts are seven and seven. Now let's look at the cubes. Let's count the cubes together carefully. One, two, three, four, five, six, seven. I've got seven in one part. What do three, four, five, six, seven. I've got seven in the other part. Seven plus seven is equal to 14. Both parts are equal. They are the same. Now let's look at the top beads string. One, two, three, four, five, six, seven. I've got seven on one side. One, two, three, four, five, six, seven. I've got seven on the other side. Now that one was a bit tricky because the colour changed on the bead strings, So don't let it trick you. Seven plus seven is equal to 14. Both parts have seven, they are equal. Let's try the bottom one now. One, two, three, or five, six. One two, three, four, five, six, seven, eight. Oo, are those two parts equal? They're not are they? But if we count them all together, let's count them all together. You ready? One, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14. So the whole is still 14 just like all of the other representations but are the parts equal? No. So even if the whole is the same, we need to make sure that the parts are shared equally. Double means two equal amounts added together. Say that again. Really well done. I think you're fantastic at doubling now, so we are ready to move on to half. Now we're back at the market and there are big signs everywhere. They say half price sale. Have you ever been shopping before and seeing signs saying a half price sale? Now, normally everyone has got a big smile on their faces when they see that, because it means that the items that they want to buy cost much less than usual. In fact, they cost half the amount, but what could half mean? Let's have a look with the example of the boots. Now, the boots, can you see them on the market? Can you spot them right at the end? the boots were 10 pounds, so that's how much they cost. But they are now half price. Half means that the whole has been shared into two equal parts. Look, it's that equal parts again, just like when we were talking about doubling. But this time the whole has been shared into two equal parts. Do you think you can read that out to me? That's right, half means that the whole has been shared into two equal parts. If we take our example of the boots, we knew that the boots cost 10 pounds, let's double check that we've got 10 pounds in the whole. One, two, three, four, five, six, seven, eight, nine, 10. Good. That's the whole, that's how much our boots cost, but today is a half price sale. And we know that half means sharing it equally. So we need to share that 10 pounds equally into the parts on our whole part model. So we move the pounds across, taking it in turns, making sure that they're equal. And look, we can count carefully to make sure that we have the same number in each. Let's count together. One, two, three, four, five, five coins in one part. One, two, three, four, five, five coins in another. Let's just double check that it all still adds up to 10. That's counting them all together. One, two, three, four, five, six, seven, eight, nine, 10. Yes, the whole is still 10, but I've shared that whole equally two parts. The boots originally cost 10 pounds. They are half price. Now they cost? Five pounds. Do you think you'd prefer to buy a pair of boots that cost 10 pounds or the same pair of boots that cost five pounds. I know I'd prefer to definitely pay the half price. Now let's see if you can do that. Just like we did with the doubling, you're going to look at these representations and you need to tell me which of them show half of 12 and which don't, and why. Look very carefully at the amounts in the parts. So you've got the whole and you've got the parts. Which of these number show half of 12. Pause the video, have a go, and then we'll check together. Let's check. Look at the first number bond. I can see that the whole is 12. I've got a 10 pound note and two pound coins, 10, 11, 12. The whole is 12. Now let's look at the parts. I can see in the top part, I've got a five pound note and a one. Five plus one is equal to six. So I have six pounds in that part. Now let's look at the other part. Oh, look, I have a five pound note and a one pound coin. It's exactly the same as the other part. Five plus one is equal to six. So this representation, the whole is 12, the parts are six and six. The two parts are equal. So this does show half of 12. Now let's look at the number bond underneath it. I've got the whole again. Should we count the pound coins to make sure that they add up to 12? One, two, three, four, five, six, seven, eight, nine, 10, 11, 12. Good. The whole is 12 again, now let's count the parts. What's in the top part? One, two, three, four, five, six. I've got six pound coins in the top part. One, two, three, four, five, six. I've got six pound coins in the bottom part. Six plus six is equal to 12. Are both of the parts equal? Are they exactly the same? Yes. So that shows half of 12. Now let's look on the other side. The top number bond, let's check the whole first. One, two, three, four, five, six, seven, eight, nine, 10, 11, 12. I still have 12 as the whole, just like with the other number bonds, but what are the parts? I can see at the top I have one, two, three pound coins. But in the other part, I've got one, two, three, four, five, six, seven, eight, nine. Now I know from my number bond knowledge, that nine plus three is equal to 12. So they still add up to 12, but are the parts equal? No. So does this show exactly half of 12? No. And the bottom one, look there's a 10 pound note and two pound coins, 10, 11, 12, the whole is 12. The top part has a 10 pound note and the bottom part has two pound coins. 10 plus two is equal to 12, but are the parts equal? No, they're not, are they? So that representation does not show half. Oo, that was some hard work, wasn't it? Shall we give ourselves a rainbow crack for our really good effort? You ready? Rainbow. Ah. Good rainbow crack everyone. So to double check, half means that the whole has been shared into two equal parts. Now it is your turn to do your independent task. And you were so lucky you went shopping and there was a half price sale on. And the items for sale were rubber, a pencil, a comic, and a pen. Now these items are in the half price sale, and the price tags show the original price. So that shows how much they cost. But can you work out how much they cost now that they are in the half price? You can use the whole part model that's been provided, or you can draw one out for yourself as well. And you can also use some objects to help you count. So you might like to just use your knowledge of how to double and half with your knowledge of number bonds, but you might have to use some different objects to move them across, to help you count accurately. So you might like to do this. I used pieces of pasta. So I chose the rubber first and I can see that the rubber costs 16 pence, but my rubber has gone into the half price sale. Now, what did I learn about half? Ah yes, both of the parts need to be equal. So I've got my whole 16, I've got 16 pieces of pasta and I need to share those parts equally. So we move them into the parts. And it looks like this. Let's double check that we've got the same amount in each. One, two, three, four, five, six, seven, eight. One, two, three, four, five, six, seven, eight. Eight plus eight is equal to 16. 16 is the whole, the parts are eight and eight. Are they both the same? Yes. So half of 16 is equal to eight. Now, once you've done that, you have a challenge independent task two. This time there is still a half price sale, but the difference here is that the prices shown is already the half price. So can you figure out how much the items cost before they went into the half price sale? I'll give you an example. If I pick the sweet, it now costs 11 pence. So in the half price sale, it costs 11 pence. But how much did it cost before it went into the half price sale? I know that half has to be equal. So if I double that I will find the whole. So I have one part that needs to be 11 pence and another part that needs to be 11 pence. And if I add those two together, then I will find the whole. Can you see here the magic between half and double? Let's count those parts carefully. One, two, three, four, five, six, seven, eight, nine, 10, 11. I've got 11 in one part. One, two, three, four, five, six, seven, eight, nine, 10, 11. I've got 11 in the other part because the sweetie now costs 11. If I add those two together, I will find out how much the sweetie cost to begin with. Double 11 is equal to 22. 11 plus 11 is equal to 22. Have a go now and then check the answers. How did you get on? Let's look together, shall we? So we already did the rubber together. We know that double eight is equal to 16. Then the pencil originally it costs 10 pence, but when it went into the half price sale, it then costs five pence. Five plus five is equal to 10. Double five is equal to 10. The comic book cost 20 pence, but in the sale, the half price sale, it costs 10 pence. 10 plus 10 is equal to 20. Double 10 is equal to 20. The pen cost 14 pence. Seven plus seven is equal to 14. Double seven is equal to 14. Compare your answers now and Mark them off for yourselves. If you didn't get it right, don't worry. You can always practise again. Let's check the next one. So this one was a half price sale where you already knew the half price. So the sweet cost 11 pence, but originally it costs 22 pence. 11 plus 11 is equal to 22. Double 11 is 22. The half price cost of the sweet was four pence. Four plus four is equal to eight. Double four is equal to eight. The other sweet originally cost 12 pence. Six plus six is equal to 12. Double six is equal to 12. And the last one, in the sale, it costs nine pence. Originally it cost 18 pence. Nine plus nine is equal to 18. Double nine is equal to 18. That was absolutely brilliant maths everybody. Now, I hope you've had fun today. Really, really well done for all of the learning, you were fantastic mathematicians. I wonder as a super challenge, if any of you at home could make your own pretend shops. You might like to find items from around your house and you could make labels and put the costs on in pence and pounds. And then you could invite people who you live with to come and buy the items from your shop. Maybe they'll be lucky enough to have a half price sale on, and then you can work out how much the items cost. So let's do the final important thing. We need to wake up Headwig. Come on Headwig, wakey, wakey. Are you ready to explain to Headwig all of the things that we learned today? What did we learn about? Well, we've learnt about doubling and we've learned about halving. But what do we now know about doubling? We know that doubling is when you add two equal parts together. The most important thing Headwig is that they are equal. And we learned that as well with our halving. Halving is when you share two parts. Again, they have to be shared equally. So the word equal comes up in doubling and it comes up in halving. We used our knowledge of number bonds to help us find the amounts in money. Do you understand? I think we did some really good explanations today everybody. Well done and bye.

To find double and half of an amount of money

To find double and half of an amount of money

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UnitMaths / Multiplication and division

Maths