Video: Finding missing factors and products, using knowledge of the two times table

﻿Hello. It's Mrs. Whale tuned in here again, and I'm going to be doing your math lesson, Okay. Let's get started, Miss Mona, last lesson want to, teach you to go away and practise the roll into some, getting to shape. So let's see if you've been practising and I've been practising too. So are you ready? High road. Good is gold. Let me see your fingers. Relevant twos. Palms up three, two, one go two, four, six eight. Who do we appreciate? ten, twelve, fourteen sixteen. Do you want to hear some more, eighteen, twenty, twenty two, twenty four. Stop. Well done. So we've just practised our two times tables using our fingers. Should we do it one more time? Okay. Are you ready? High road. Good is gold. Let me see your fingers relevant twos, palms up, three, two, one go two, four, six, eight. Who do we appreciate? ten, twelve, fourteen, sixteen. Do you want to hear some more eighteen, twenty, twenty two, twenty four. Stuck. Well done. Fabulous. Right? Our brains. Most people warm now. Should we get on some WIC? Fabulous. Okay, so we've got a question. How many eyes do the children have all together? So let's have a look at the slide. We've got an equation at the bottom, but what do you notice about the equation? That's right. The product is missing. Isn't it? And we need to find out we need to work out the product, but let's, let's just break it down. Okay. What does the three represent? What do you think that three represents? Okay. The three represents the groups. Okay. How many groups we have? So how many children there are? What do you think the two might represent? Fabulous. The two represent the eyes. Doesn't it? So the three represents how many groups we've got and the two represents how many is in each groups. So how many eyes does each person have? So to find the product, we can chunk it into twos. Like we've just done. Oh, you might know what three twos is. So let's chant, Lets practise by chanting, So one two is two, two twos, a four, and three twos are fabulous. Three twos are six. So the product of three and two is' six, well done. Let's have another go at something different. Okay. So now we've got another question. How many eyes do the children have all together? What do you notice about this equation? Hmm That's right. We've got two missing numbers. We've got a factor missing and we've got the product missing. So how do you think we can work this one out? What do you think we could do, to find the missing numbers? Well Let's have a look at what we know. So we know that the group size is two, as each person has two eyes. How many people are there? That's right. There's four people. There's four children in the picture. So four must be a factor. And that factor tells us , how many groups we have. So the product, a four and two, right? Hm. We can chant in the twos. But if you know what four twos are, you might already know. So do you want to just pause the video and try and work out, what the product of four and two is? So the product of four and two is eight. Fabulous. And you might, you might've chunked it and that's okay. But you might have already, known that multiplication fact. Well done. So four times two. So four times by two is eight, the product of four and two is eight. Fabulous. Right? know, that practise. We've got another question another picture and another equation. Look at that equation. Okay. So how many eyes do the children have all together? And the equation is, like the last equation. Isn't it? On the last slide we've gotten missing factor and a missing product. Can you remember how to work out the factor and missing factor? So let's think We know that our group size is two but, How many children are in this picture? So how many number of groups do we have? That's right. We have seven. So, our number of groups is seven, which is the missing factor. So what is seven twos? You might want to chant or if you know what seven twos are, you can just shout it out. So let's say together, seven twos are fabulous. fourteen, seven twos are fourteen. Well done. Okay. Right. I know the problem. How many eyes do the children have? What do you notice now, about the equation at the bottom? that's right. We've got missing factors, and a missing product and we have to find out what the missing factors are and what the missing product is. How do you think, we can work out the missing factors? Well, let's start by looking. How many, how many groups we've got? So how many groups do we have? Fabulous. We've got five groups because there are five children. Okay. So five must be our first missing factor. Now I've got to work out, how many eyes the children have. So what is going to be the number, the next missing factor. Fabulous too, because each child has two eyes. There are five children and each child has two eyes. So five twos, now we need to find the product of five and two. We can chant it. Or if you already know that multiplication fact you might already know the product. So can you tell me, what the product of five and two is? Fabulous. Five twos. And can you see how we had to work out the factors before we found the product, and we didn't have any factors? Did we? Fabulous. You've worked really, really well so far. You're really good at this. The more you keep practising , your multiplication tables the easier this will be. Okay. Let's have a look at something a little bit trickier. I think you're ready for a bit of a challenge. Can we have a look? Okay. Well, done, now I've got a word problem for you. What is the product of four and two? well, you could draw this. So I decided that I would use some shoes. Okay. So there are my shoes. And I'm also going to, write the equation underneath. Okay. So there are my shoes and my equation is there underneath just like we had before on the previous slides. So I need to work out. How many groups do we have? So how many groups do I have on this slide? That's right. I have four. So I going to put four as one of my missing factors. How many shoes? I mean each group. So how many is in each group? That's right. We've got two. So now the product of four and two, we need to find that product. Don't be that missing product. So again, you could chant in your twos or if you already know what four twos are, you will know the answer. So what is the product? Of four and two? Fabulous. The product of four and two is Eight. Okay. Let's have a look at another word problem. Okay. I've got eleven, two P coins. How much is this all together? So again just like the previous slide, you can either draw it or you can actually go and find eleven, two P coins. So I have decided that I will draw it. So how many kinds will I need? I need eleven. So we've got my eleven, that's five, ten, eleven. Okay. So I've got my eleven, two p coins and I'm going to put my equation, at the bottom to help me. Now, I need to know how many groups do I have. Okay. So I've got eleven. And how more, how many are in each group too? Because we've got eleven, two P coins. So eleven twos. Now, how much do we have all together? So to work this out, I just need to know what the products of eleven and two are. Can you tell me what eleven twos are? again, you might need to chant it or if you already know what eleven twos are you might be able to shout out super. eleven twos. is twenty two. So we've got twenty two P. So how much all together? Well, we've got twenty two P, cause we have eleven, two P coins. Oh, you're so good at this now. Fabulous. Let's have a look at another one. Okay. One of the word problem. If the product is twelve, and one factory's two. What is the other factor? So what I'm going to do, and you may want to do this as well, is I'm going to write the equation underneath the word problem, just to help me. Okay. Cause we need to work out what the other factor is. So I'm going to write it out as an equation and I'm going to, use the information from the word problem. So what is the product? Well, we know that the product is twelve Okay. We don't know how many groups we've we've got, but we do know that in our groups we have two, because one factor is two. So can you say we're trying to work out One of the missing factors and the missing factor. We're trying to work out with how many groups we have look at my equation. Is my equation the same as yours? Or is it different to yours? If it's different? Why is it different? Why do you think your equation is different to mine? Do you notice that, I put the product at the beginning of the equation instead of at the end and you might've put it at the end and that's okay. Does it matter whether the products and the equal sign is at the beginning of the equation or at the end of the equation? No, it doesn't. It does not matter. And you have done this before. On previous lessons, but it's just to remind you that it doesn't matter whether your equal sign is at the beginning or at the end of the equation. Okay. And I'm going to I want to complete my equation, just like this. So we need to work out how many groups we have and I'm going to use objects or images and you might want to do the same or, to draw them. Okay. Or if you already know what you need to do to fill in that missing number box, you can fill it in. Okay. You might already know what something times two equals twelve is. You might already know what that missing factor is. And if you don't that's okay because we're going to go through it now. So I have you saw okay. And I'm going to counting twos until we get to twelve. Why do you think I'm going to stop at the number 12? That's right. Because twelve is our product. 12 is our answer. Okay. So let's count counting twos. till we get to twelve, two, four six. So we have he look, we have one two is two, two twos, a four, three, two the six. Okay. Let's carry on, four twos are. Eight, five two are ten, six twos are twelve. Oh okay. Why have I stopped? Why have I stopped now? That's right, because we were waiting until we got to twelve, because 12 is our product. So how many groups of socks do I have SIPA?

I have six.

So six twos are 12. Fabulous. And I will write that in Mummy's inbox. And you can also write it like this. 12 is my product. Say X is my group size and six is how many groups you've got. And two is how many is in each group. Okay fabulous. So the project of six and two is 12. Do you see how we've used? Just right by writing the equation, how we've used that word problem and wrote out the equation underneath. Do you see how he works it out and you might have already know the answer what the missing factor was and if you did that's really, really good. Okay. It's just about practising those multiplication tables. It's all about practising your two times tables. It's really really important that you know, no two times tables so that you can answer questions, just like these. Okay. So this is your practise activity. All right. Now this is your ratio chart that you might remember from last lesson. Okay. And if you've, if you've lost it, that's okay. You can just make a new one, but it looks like this and your practise activities to go away and draw pictures for each multiplication fact. Now, when you draw a picture, it's really really important that you say in the multiplication fact as you draw the picture, it's an opportunity for you to practise your two times tables. It does not matter whether your pictures beautifully drawn or coloured in, It's not really about the pictures. It's about you having the opportunity to practise your two times tables. Okay? And when you draw for each picture you need to be saying the multiplication facts. So for example, the first one, I will say one, two is two and there I have drawn two choose the next multiplication facts. I will say two twos are four and there is my picture and so on. But I am saying my multiplication facts as I draw the picture it doesn't matter whether you pictures are coloured in or whether you cannot can't draw as long as you are practising your multiplication facts. Okay? So that's the most important parts of this activity right, That's it for today's lesson. And I think you've worked really, really well. So well done, I want you to go away. I want you to practise your multiplication facts and I will see you. See you bye bye

Lesson summary: Finding missing factors and products, using knowledge of the two times table

In this lesson we will draw a picture for each multiplication fact to illustrate the ratio chart. We are going to find missing factors and products, using our knowledge of the two times table and a number line.

Maths

Y2 Maths

Key Stage 1

Year 2

Finding missing factors and products, using knowledge of the two times table

The two times table

UNIT

Practise counting in twos

Introduction to the terms factor and product

Embedding the language of factor & product, making connections between different representations

Explore 0 x 2

Record the two times table in a ratio table

The two times table: Looking for patterns and relationships

How to find an unknown using a known fact

Varied Practice Applying Knowledge of the Two Times Table

Writing the two times table in two ways

Practise saying the two times table with 2 as the first factor and as the second factor

Equations with Expresssions on Either Side with the Group Size of 2

Finding missing factors and products, using knowledge of the two times table

Video

Lesson summary: Finding missing factors and products, using knowledge of the two times table

Browse Oak's lessons: