Which times-table can we double to find our 12s?

Using doubles to multiply

Key Stage 2

Maths

Multiplication and division

﻿Hello there, I'm Miss Brinkworth. I'm going to be going through this math lesson with you today, let's look at the learning objectives together, we're going to be using doubles to multiply. So this is a really lovely trick to learn. 'Cause what we do is use your known times table knowledge focusing mainly on your just your threes and fours. And we can use them to help us with unknown times table questions. So it's a really, really useful skill. So let's have a look at our agenda. Like I say, It's mainly using three and four timetables today. So we're going to recap on that at the start of the lesson. We then going to relate these to your to your threes and your sixes. Sorry I should say your six and your eight. So we're going to relate your threes to your sixes And then we're going to relate your fours to your eight. so you can see how it's doubling The three times table Is going to help us with our sixes and our four times table is going to help us with our eights, And at the end of the lesson, there'll be some independent work, a chance for you to have a go at this learning on your own in your independent work, come back and check the answers together. And then that Exit quiz to see how well today's learning has gone in. So you don't need much for today's lesson, just a pen or pencil and some paper, "I can do" attitude, Is going to get to you a long way as well. So pause the video and get what you need. Welcome back! Well done. Let's get started. So your warm up for today, Have a think about your threes and your fours. Can you underline any number here, which is a multiple of three and circle any that are, are multiple of four? Have a good look at the ones which appear in both and for your challenge, Can you find one more number? One more number which is most both a multiple of three and a multiple of four? Come back when you're ready for the answers. How did you get done? Should we look at our answers together? I'm hoping you found all of your multiples of three. Let's have a look. Nine is a multiple of three. That's three times three. And 12 well that's three more, so that's four times three. Six we know is two times three, and 18, well 18 is, three lots of six. So it must be six times three. Any other three value you found? 21 plus three added to 18. So that must be seven times 3. 24 is three more again. So that's eight times three. Well done if you found all of your threes in there, everybody. On to three fours, just three 12 and 24. But we can see that both of them appear in the three times table as well. Were you able to answer the challenge and find one more number which is in both the threes and the fours? I found 36. That's the next one. But isn't the only one so well done if you found a different number. Okay, let's move on to today's lesson then. So, your teacher tells you to put three pencils on each table, There are three tables. How many pencils do you need? Well, we can draw up our models. To help us comprehend, we can think about our three tables. And we know that we need to put three pencils on each table. So we've got three groups of three, how much is that all together? three times by three is nine. So, well done! if you could see that three times three is nine. And that's another pothole model there. Just to make it clear what we're doing, we've got three groups, and they're coming together to make the hole. Which in this case, is nine. Now, that's probably a fact, that you feel quite confident with, three times three is nine, you probably don't need to draw out a bar model or a pothole model for it. And that's fantastic. So what we going to be be doing today is using those times tables that you feel very confident with and applying them to larger numbers. So thinking about how we can use our three times table to help us with a larger times tables which we maybe don't feel quite so confident on. Your teacher tells you now to put double that number of pencils on each table. So we need to double three. What is double three? Double Three, two, lots of three is six. So this time, we need to put six on each table. Okay, so we've got three groups of six. Now, we're doubling our last question. Instead of putting three on each table, we're putting six, double the number on each table. So instead of three times three, we've got three times six. What was our answer for three times three again? It was nine, wasn't it? Well, what we can do is double our answer for three times three, to get that three times six. So the first time, you got three, lots of six. And if we double nine, we get the answer 18. So what I'm showing you here is that you might not think you feel quite so confident with your six times tables as you do with your three times tables, but you can use them to help you and that's because double three is six. And so that's why those times n six was have such a close relationship. If you know what three times three is, you can double that answer of nine to give you the answer 18, to six times three. And obviously, you can do them in either order three times six, or six times three, whichever one you feel most confident with. Okay? So when we double one factor, we double the product. So we know that the factors are the numbers that we multiplied together to get our product. Do you think it's always true that if one of the factors gets doubled, the product gets doubled? So that's the question then we just looked at. Three times three is nine. And then if we double that for three times six, we get 18. What about this question, then? two times three, or three times two is six. What about three times four? We're hoping that the answer will be double six. What's double six? well double six is 12. So it looks like this rule is true. If we double one of the factors, we doubled the product. And that means that we can use our known times table knowledge to help us with times tables that maybe we're not quite so confident with. Be careful there, we only double one of the products. So you can see in those questions, three times three has turned to three times six, not six times six. Again with the second question, three times two has turned to three times four, not six times four. So for this question, for this and skill that we're learning today, where we can take our known times tables, and double them to help us with the ones we don't know, we're only going to double one of the factors. Okay, so moving on, then here is what we've, another question. If we know four times three is 12. Then we can use that to work out four times six. We can apply it to our six times tables, we can double 12 to find 24. So we can see, that if we times something times by six will always be what double was it was times by three. So in those blue squares, we could put any number and it would come true. If we're double. If we're trying to find the six times table, we can double what it is in our three times table. Okay, what do you think is being shown here, then? Pause the video for a second and have a look. Well, hopefully you can see these are number lines are showing you the relationship that top one between your threes and your sixes. And making it clear why your threes and sixes have that really close relationship. Because six is double three, three is half of six. So one times three is three, and one times six is six. Six takes two jumps of three for every one of its times tables because it's double. So if I know that one times three is three, and I know that one times six is six, I can then use that to double for my other answers. So for example, I know that four times three is 12. So I can double that to find the answer for four times six, which is 24. The next row down is showing another multiplication relationship. Can you see which times tables are being compared in that number line at the bottom there, we've got our four times table going across the top and our eight times table going across the bottom. And just like our threes and sixes, eight and four have got that double relationship, because eight is double four, four is half of eight. So for every jump of eight, it's going two jumps on our fours. So again, I can see that one times four is four, and one times eight is eight. And then if I go to four times four is 16. I can double that for four times eight is 32. Hopefully, as we move through this and you become more confident, you can do these multiplications, these doublings in your head, but for today's lesson if you would like to draw out bar models or numbered lines like this, that's absolutely fine. Okay, pause the video here and see if you can use what we've just learned about doubling our threes and fours to find our sixes and eights to find the missing numbers. This is nice and easy because I haven't even made you remember your threes and fours. I've given you those facts there. All you need to do is double them to find the ones that are missing. So come back for the right answers. How did you get them? So if we know that five times three is 15, we can double 15 to find five times six, doubling 15 where we double the five gives us 10. And double the 10 gives us 20, 20 add 10 is 30 If three of eight threes is 24, we can double that to find eight sixes. 24 is lovely and easy to double. Because there's no regrouping needed. we double the four to give us eight and we double the 20 to give us 40, 48. Okay, four times four is 16. That's when we always have to remember, four times four is 16. That's when that I always make a mistake on. So I try to remind myself of it as often as possible. Four times four is 16. Four times four is 16. I'm going to double that to find four times eight. So I have to think about that, is 16 is just one more than 15. I know that double 15 is 30. So I need to add one more from each of my 15. 'Cause I've got 16. And so my answer is 32. Well done if you got that one. And then again, we've got 24 doubled here, and to give us 48 We've already talked about that answer. So well done if you got that one, right. Okay, so time for your independent task. Take as long as you need to have a practise of you're doubling. And we'll come back and talk about our answers together. really well done for having to got that independent task, everybody. Let's look at the answers. Now, there's lots and lots of factor pairs here and I'm just going to go through a few of them, because you going to get very bored of my voice. If I go through absolutely all of them, I'm hoping you found them all, you've managed to draw lines between them. And you've been able to use your threes and four times tables to help you with your sixes and eights. So I'm just going to go through a couple, I'm sure you've done more. So I know that one times three is three, I can double that to find this part here, one times six, which is six. Another one is that four times four is 16. And I can double that to find this part down here, which is four times eight is 32. Really, really well done if you saw that, and four, five times four is 20. And again, I can double that here to find five times eight is 40. 20 is a lovely one to double 'cause we just need to double our 10s column. There's nothing in the ones column. That's a really nice factor, remember, you probably feel quite confident knowing that four times, five times four is 20. Now you can feel more confident as well knowing that five times eight is 40. As it's double the Four times table. And just going back, really well done, if you've matched all of those up, that's fantastic. Sorry for not showing you all of them. But it would have just got very messy. And like I say, I think you would have got a bit bored of me, hearing my voice. Let's have a look at these ones, then. It's just about reading statements and seeing if you believe them if they're always sometimes or never true. So you can find the six times tables by doubling your threes. You absolutely come out always true. So if you're stuck in your sixes, always go back to your threes to help you. Second one, that says you can work out answers to the five times table by doubling the fours. No, that's not true. That's because five and four don't have that double relationship. Well done if you could see that. Eight is double four. So knowledge of the fours, can help us with the eights. It absolutely can. Yes, we've talked about that one in our last lesson. Number four then, it says if I know that two times two is four, I know that four times four is eight. Well, this person has made a slight mistake here and that they have doubled both the factors and so instead of doubling One. So instead of using two times two to work out two times four, they've changed it to four times four. So that one's not quite correct. Four times four is actually 16. So be careful when you're doubling it works when we're changing one of the factor pairs, not both of them. And could six times tables help us with our 12s? Just a little challenge for you there. Yes, it can. And that's because we know that 12 is double six, six is half of 12. So you could apply today to learning to your sixes in your 12 as well. Really, really good. I would love to see your working out for today everybody, how well you've got on with all of those factor pairs in the first part of the independent work. So if you'd like to please ask a parent or carer to share your work on Instagram or Facebook or Twitter, tagging @OakNational and #LearnwithOak. But before you go, please have a go at that final knowledge quiz which is going to really just see how much today's learning has gone in. You've worked incredibly hard today, everybody really well done. Enjoy the rest of your learning today, bye bye.

Using doubles to multiply

Using doubles to multiply

Slide deck

Lesson details

Key learning points

Licence

Video

Worksheet

Exit quiz

5 Questions

Lesson appears in

UnitMaths / Multiplication and division

Maths