## Level 4a

# Measurement and Geometry

## Chapter 10 - Using Measures

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**Overview of the chapter**

**Rich tasks**

- These are problem solving open-ended questions that require students to investigate problems involving choosing appropriate scales, units and measuring devices. The tasks can be given at the start of a topic and done as the students gain enough knowledge to complete them, inserted into a topic at an appropriate place or given as homework or extension.

- Small stuff
- Rolling, rolling, rolling
- Did you get some sleep?

> More on "Rich tasks for this Chapter"...

**1. Small stuff**

- As each item is too small to measure individually students will need to choose an appropriate large number of the items to measure and then divide that measured amount by the number of items. For example, students may choose to weigh 100 paper clips and then divide the weight by 100.

**2. Rolling, rolling, rolling**

- This could be used as an activity where students build the ramps at home and bring them to school to check the times.
- You could ask the technology teacher to help students to make the ramps.

**3. Did you get some sleep?**

- Students will need to make some assumptions about the food that people will eat on the sleepover.
- Students may find that carrying out a short survey in the classroom will assist them with this. This is a good opportunity to introduce some statistical work into a measurement task.
- The list of food and drink items is not exhaustive; students may want to add other items.

**Choosing units and devices**

- Select appropriate units in different contexts and choose the appropriate measuring device.

> More on "Choosing units and devices"...

**Students should already know points 1 and 3.**

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**Teaching ideas**

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** Getting started (Getting started sheet 10)**

This link displays the Getting started on page 170 to use as a class discussion. You could extend this discussion and ask students why kilometres AND metres AND centimetres AND millimetres are all needed to measure length. You could ask questions like ‘Can you measure a stamp using metres? What is a better unit to use? Why? And so on.

**Discussion**

Use the discussion on page 174 as a class discussion. You could divide the class into groups and then ask each group to report their findings to the class.

**Abbreviations**

Divide the class into groups. Ask questions about the abbreviations for units such as “What does km stand for?” or “What is the abbreviation for litres?” The first person to answer takes a point for their group.

**Teacher notes**

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- Point out that units of mass, capacity and length are related to physical objects whereas time is not.
- It is important that students know the approximate size of all metric and time units. This is best consolidated by students working with familiar items in their world, associating them with lengths, masses, capacities and time.
- Make sure students know the abbreviations for the metric units.
- Students should know that 1 tonne is 1000 kg. This could be introduced into the discussion on page 174, by saying that 1000 g is called 1 kg so 1000 kg has to have a specific name.

**Estimating measurements**

- Use a known or familiar measure as a comparison to help estimate an unknown measure in a contextual situation.

> More on "Estimating measurements"...

**Students should already know points 1 and 3.**

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**Teaching ideas**

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**Closest estimate**

Play the *Closest estimate* game on page 175 as a class game. You could allocate 4 points for the second closest estimate.**Compare it**

You could use the discussion on page 176 to discuss how to use known measures to help estimate unknown measures.

**Teacher notes**

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- Encourage students to think of a suitable unit and range for a measurement first before making a final estimate.
- Encourage students to compare to objects for which they know the approximate measurement. Example: If they know how much a litre of milk is then they could use this to compare the capacity of other amounts.

**Reading scales**

- Read linear scales where measurements are given to two decimal places.
- Estimate readings on a scale when only some of the divisions are shown.

> More on "Reading scales"...

**Students should already know points 1 and 3.**

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**Teaching ideas**

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This link displays scales using whole numbers, tenths and hundredths.

Students can be asked about the size of each small division?

If students count the divisions they will see if counting in ones, tenths or hundredths works.

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**Teacher notes**

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- Some students have difficulty reading scales if the intervals do not go up in ones. Encourage them to work out what each interval represents before attempting to read the scale. Count up from one large dash to the next to see if it works.

Example: If a student counts 5.1, 5.2 and so on for this scale.

they will realise that they won’t be able to reach 6 by counting in tenths.

- Ensure that students write units with their answers.

**Estimating and measuring**

- Estimate and measure length, mass, capacity and time using appropriate measuring devices.

> More on "Estimating and measuring"...

**Students should already know points 1 and 3.**

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**Teaching ideas**

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** Practical (Printable Master - Practical, Question 2)**

Set up four stations, one for each task, and students could rotate through them. The task cards for each station are available here. - Encourage students to plan what to do for each question before starting to do it.
- Encourage students to write down how they carried out the tasks, to record their results and write down what they learnt.