Video: Compare unit fractions in a measure's context

﻿Welcome and hello. My name is Miss. Wilken and I will be teaching you about fractions today. We are going to be comparing unit fractions but we're going to look at them in a different way today. We are going to use capacity and measure to help us. How did you challenge your family, in "Would you Rather" the game show that Mrs. Kingham showed you yesterday? Mrs. Kingham asked me a question as part of that game show too. Mrs. Kingham asked me if I would rather have one third of a bag of Brussel sprouts or one quarter of a bag of Brussel sprouts? I chose to have one third of a bag of Brussel sprouts. Do you think I like Brussel sprouts? Refer back to the STEM sentence that you learned yesterday. Which is, when you compare unit fractions, the greater the denominator the smaller the fraction. You're right. I love Brussels sprouts. They are my favourite vegetable. Would you prefer to have one third or one quarter of a bag of Brussel sprouts? Today we are going to compare fractions by using measure. We are going to start by using capacity. Capacity is the total amount of liquid a container can hold and I'm going to need you to help me. I want to fill my container so that it is about one third full. I need you to shout, "Stop!" When it's about right. How will we know when I have filled the container one third full? If I pour the same amount of water three times into the container, then the container will be full to the top. You're going to need to imagine that the container is divided into three equal parts. Right, get ready to help me by shouting, "Stop!" When I fill it to about one third full. Perfect. Thanks. Let's see what one third looks like or my picture of my container. Point where you think the water will stop. Let's fill it. How accurate were you? This time, I would like you to shout, "Stop!" When the container is one quarter full. Do you think there will be more or less water than last time? How would you explain it to somebody? If I'm filling the container up, so that it is one quarter full, how many equal parts do you need to imagine the container is broken down into? You're right. We need to imagine the container is divided into four equal parts, which is more than last time. If we have more equal parts, then each part must be smaller. Right, get ready to tell me when to stop. Tell me when you think I have filled the container one quarter full. Brilliant, thank you. Let's see what one quarter looks like on a picture of my container. Place your finger on the container where the capacity of the container is one quarter. Right, let's fill it. How accurate were you? What have we proved by filling our container up by one third and one quarter? We have proved that one third is larger than one quarter. As the whole has been split into three equal parts. Whereas when we measured as a quarter, we split our whole into four equal parts. Therefore a quarter is smaller than a third. This thinks back to our STEM sentence of, the greater the denominator, the more equal parts there are. And therefore each part is smaller. What do you think is going to happen when we fill up our container to one 10th full? I filled up this container one 10th full. Can you convince me? How would you explain it? You can use the starter, I know that... Let's do it together. I know that if I had the same amount of water 10 times, it would fill my container to the top. You have imagined that the container has been divided into 10 equal parts and I have filled it up. So that it is one 10th full. Let's see what one 10th looks like on a picture of my container. Place your finger on the container where you think the capacity of a container will be filled to one 10th. Let's fill it. Oh, there we go, it's one 10th full. How accurate were you? I have put these unit fractions in order. True or false? Don't forget our STEM sentence and what these fractions looked like when we poured them. In the right hand corner of the screen, I've put our STEM sentences to help us, which is, when you compare unit fractions, the greater the denominator, the smaller the fraction. So have I ordered these fractions correctly? You're right. I've made a mistake. The answer is false. I ordered the fractions thinking that the smaller the denominator, the smaller the fraction. But we know that actually the smaller the denominator, the larger the fraction. So my largest fraction is one third. And my middle fraction is a quarter. And the smallest fraction is one 10th. What if I'm filling my container to 1000 full? Will it be more or less water than last time when we filled the container one 10th full? Remember that the more equal parts a whole is divided into the smaller each equal part is. You're right. It will be even less water than last time. It won't even float as a thousand is a tiny amount. Get ready to tell me when to stop. You are going to have to be super speedy. Let's see what's one thousands will look like on a picture of my container. Place your finger on the container where the capacity is 1000. Let's fill it up. How accurate were you? Here our estimated unit fractions that we have poured. Here is one third, one quarter, one 10th. And 1000. You can see that one third is a larger unit fraction than 1000. Which proves our STEM sentence which is, that when comparing unit fractions, the greater the denominator, the smaller the fraction. Let's look at comparing unit fractions using a different measure. This time we are going to use length and use a metre stick. Half a metre means the metre stick has been divided into two equal parts. So here you can see there's one equal parts. And here you can see the second half which is the second equal part. Let's use our metre stick to look at quarter's. One quarter of a metre means the metre stick has been divided into four equal parts. There's one quarter and one equal part. There's our second quarter and our second equal part. Here's our third quarter and our third equal part. And here is our full equal part and our fourth one quarter. Here we've got our metre stick again. And we know that half a metre means our metre stick has been divided into two equal parts. We know that a quarter of a metre means our metre stick has been divided into four equal parts. How many equal parts would make one whole if my unit fraction is one 10th? You're right. There will be 10 equal parts. How many equal parts would make one whole if my unit fraction is 100? You're spot-on, there will be a 100 equal parts. Have I ordered these fractions in descending order correctly? Descending means fractions are ordered from largest to smallest. STEM sentences can be really helpful. So let's look at ours from today's lesson. Again, it's in the corner of your screen. And it says when you compare unit fractions, the greater the denominator, the smaller the fraction. So using my STEM sentence, I know that one fifth is the largest unit fraction. 64 is the largest denominator. So I know that means it must be the smallest fraction. 10 is a smaller denominator than 24. So one 10th is bigger than one 24th. So one 10th needs to come after one fifth and one 24th needs to go in between one 10th and one 64th. I'm going to explain today's task. I have two unit fractions, one half, and 1000, which unit fraction is the smallest? Which one is the greatest? You're right. One half is the largest unit fraction. And 1000 is the smallest unit fraction. Could you write down five unit fractions that could be found in between these two fractions? Well done for working so hard today.

Lesson summary: Compare unit fractions in a measure's context

In this lesson we will compare unit fractions using capacity and measure to help us.

Maths

Y4 Maths

Key Stage 2

Year 4

Compare unit fractions in a measure's context

Working with fractions

UNIT

Divide and describe the same whole when divided into differing numbers of equal parts

Understand fraction notation to represent a relationship between part and whole

Begin to use and understand the terms 'Numerator' and 'Denominator'

Name unit fractions and match them with the fraction notation and a representation

Embed previous fraction work using a linear model

Assign unit fraction names and notation to 3D representations

Assign unit fraction names and notation to equal parts of quantities

Recognise and reason about unit fractions in a variety of contexts

Understand that Equal Parts Can Look Different - Area

Understand that Equal Parts Can Look Different - Volume and Area Contexts

Compare unit fractions using a fraction wall

Reason about comparing unit fractions

Can we compare unit fractions of different wholes?

Construct a whole from a part and identify the fraction it represents

Build and compare different wholes from the same unit fractions that represent the same length

Build and compare different wholes from the same unit fractions that represent different lengths

Build and compare different wholes from different unit fractions that represent the same quantity

Build and compare different wholes from different unit fractions that represent different quantities

Build and compare wholes when different unit fractions represent different amounts

Compare unit fractions in a measure's context

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Lesson summary: Compare unit fractions in a measure's context

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