Lesson video

Hi everyone.

My name is Miss.

Sabzvari, and I'm really excited you decided to join me today for our maths lesson.

The unit we're studying is multiplication and division.

In the previous lesson, we focused on solving division problems, when sharing.

In today's lesson, we will focus on solving division problems when grouping.

So when you're ready, let's begin.

So let's have a look at today's lesson agenda.

First, we'll begin by recapping division as grouping.

Then we'll move on to a talk task where we'll explore problems, which include division as grouping.

Then we will represent our problems using bar models.

And finally, you will complete your independent task.

Before we begin today's lesson, you will need the following items. You will need something to write with, and something to write on.

You will need keeps or counters.

Alternatively, you can ask your parent or carer to cut out some pieces of paper that you can use instead.

And finally, you will need a ruler.

So please pause the video now and get the items that you need.

Division as grouping.

In the previous lesson, we looked at division by sharing, and this lesson, our word problems are going to be more focused on dividing when we are grouping.

So let's recap and find a difference between the two.

Pause the video now and tell your screen what the difference is.

Great work.

So when you're dividing by sharing, we know the value of the whole.

We know how many we have all together, and we also know how many parts there are or how many groups we have.

However, what we don't know and what we're trying to find out is the value of each part.

Alternatively when we are dividing by grouping, we still know the value of the whole, so we know the total, how many there are, but we also know the value of the parts.

Okay? So we know the value of each part, but what we don't know is how many parts there are.

Let's have a look at our problem, so follow with me.

15 pupils came into the dinner hall.

Pupils sit in tables of five.

How many tables would 15 pupils fill? I would like you to pause the video here and tell me, are we dividing by grouping or are we dividing by sharing? And why? You can use this sentence structure to help you.

I think we are dividing by mmm, because mmm.

Excellent work.

We are dividing by grouping.

So we are dividing by grouping because as we discussed, we know the value of the whole, so we know how many pupils there are, and we know the value of the parts, okay? So we know how many there are in each group.

What we don't know is how many groups there are.

Okay.

So what I would like you to do now is select your counters, and I would like you to work out this word problem by creating a rights.

Then I would like you to draw your array.

And finally, I would like you to write down your division equation.

Great work.

So we know that we have 15 pupils altogether.

So I have selected my 15 counters, and I'm going to group them in groups of fives.

I'm going to make one group of five, And then I'm going to move on, and create another group of five, and using my remainder of my counters, I'm going to make another group of five, until I run out all my 15 counters.

And here I can see that I've got one group of five to three groups of five.

So I know that 15 divided by five is equal to three.

Okay? So I know I will have three equal groups.

Or I will have three tables.

Great work.

So now that we have represented our word problem using arrays, we're going to be looking at representing division word problems using bar models.

Okay.

Let's read the word problem together.

Miss.

Smith needs 15 cookies, cookies come in bags of five.

How many bags of cookies does she need to buy? What I would like you to do is to pause your video, and tell your screen are we dividing by sharing or dividing by grouping.

And how do you know.

Excellent work.

We're dividing by grouping because we know the totals, we know the whole, and we know how many are in each group, we know the value of each parts, but we don't know how many parts there are.

So we would draw a bar model, and we know the value of one part.

I'm not able to draw every single part because that's what I'm trying to work out.

But I can draw one of my parts because I know one part is equal to five.

Okay? So please pause the video here and draw your bar model.

Excellent work.

So we know that we have got 15 cookies all together.

And we know one part has the value of five.

We want to know how many parts we are going to have until we reach 15.

So using your counters, please share your 15 cookies equally in bags of five, until you find out how many parts or how many bags of cookies Miss.

Smith will need, then we will go through the answer together.

Okay.

So I know that Miss.

Smith needs 15 cookies and the cookies coming bags of five, but I want to know how many bags of cookies she's going to need to buy.

So what I'm going to do is first, I'm going to draw my bar model.

Okay.

I'm going to make sure that I use my ruler.

And it's really important to make sure that the lines are straight.

And I know that she needs 15 cookies all together.

So that's the value of our bar model.

I know that cookies come in packs of five, okay? So I know that this has the value of five.

I need to know how many bags of cookies Miss.

Smith needs.

So what I could do is I could get my 15 counters and make groups of five until I run out of my 15 counters.

So what I'm going to do is I'm going to create a group of five.

So one, two, three, four, five, so that's one group.

And I'm going to continue making another group of five and then another group of five until I run out of counters.

So three, four, five, okay? So that's another group.

And one, two, three, four, five, and that's another group.

And I've run out of my 15 counters.

So I have got one, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15.

Yes, I've got the right amount.

And I have five in each group.

So I know that 15 divided by five, cause there are five and each group, is equal to three.

And if I wanted to complete the bar model without using my concrete manipulatives, what I could do is, I know that one group is equal to five.

So I could draw one, two, three, four, five, one, two, three, four, five, that's another group.

So now I have two fives of group, which is 10.

Then one, two, three, four, five.

All right? So I've got one, two, three, groups of five, which equals 15.

Great work.

So let's have a look at our quick check question.

Okay? So we've got two questions with two bar models, and your task is to match the correct bar model to the correct word with it.

Let's read them together.

Pencils come in packs of five.

Miss.

Sabzvari needs 20 pencils for her class.

How many packs of pencils does she need to buy? Okay? So I've got 20, I want 20, and I have, and there are five pencils in each pack.

Pencils come in packs of two.

Miss.

Sabzvari needs 20 pencils for her class.

How many packs of pencils does she need to buy? And three, two, one, excellent work.

So here, we know that we have got the whole is 20.

So both of our bar models, the whole is 20, okay? And we need to look at the packs or how many groups, okay? So in the first question it says the packs of five.

So I know that one group is going to equal to five.

So I know that this bar model is for the first question.

And that this bar model is for our second one, because this, it states that it comes, that the pencils come in packs of two.

So well done if you got that correct.

So moving on to independent task.

First what I'm going to do is read the questions for you.

And then you're going to draw your bar models.

Using your counters, you're going to work out the answer.

And then you're going to write your division equation down.

And if you'd really like to push yourself, you can draw your m dots into your bar models.

Or alternatively, you can just write down the numbers.

Okay? I would like you to decide and to choose which one is a more suitable method for you.

Okay? So let's read the questions together, follow with me.

Question A, Mr. Smith needs 10 oranges to make some juice.

Oranges come in bags of five.

How many bags of oranges does Mr. Smith need? Question B, farmer Joe has 20 eggs and wants put them in boxes of 10.

How many boxes does he need? Pause the video now to complete your task.

So let's have a look at the answers for our questions.

Well done to everybody who is passive, yet so fun, you're do so well.

What we would do initially is we're going to draw a bar model, and we know that the value of the whole is 10, we have 10 oranges.

And we know that we want to make some orange juice, and the oranges come in bags of five, okay? So I know that part one is going to be five, and I want to work out how many parts I have.

Okay? Until I get to 10.

So five, and another five, is going to give me ten.

So I know that 10 divided by five is equal to two.

And our second question, we know that farmer Joe had 20 eggs, I know that whole with bar model is 20.

And he wants to put them in boxes of 10.

So we're going to group them in tens.

So I know that 20 divided by 10 is equal to two.

Give yourself a big pat on the back if you got that correct.

Well done.

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

And now it's time for you to complete your end of lesson quiz.

You have done extremely well.

And I can't wait to see you all next time.

Bye.