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# Mathematics / Year 5 / Number and Algebra / Number and place value

Curriculum content descriptions

Use estimation and rounding to check the reasonableness of answers to calculations (ACMNA099)

Elaborations
• recognising the usefulness of estimation to check calculations
• applying mental strategies to estimate the result of calculations, such as estimating the cost of a supermarket trolley load
General capabilities
• Numeracy Numeracy
ScOT terms

Rounding,  Accuracy and precision

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### How many heads tall are you?

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### It's an estimate, not a guess!

An approximation is the nearest estimate without having the precise size or measurement of something. See how accurate estimates are made in logical ways using information about many things in our everyday lives.

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Can maths really help to save lives? In this clip we see some real life applications of mathematics. Some are about helping to save lives others are about how maths can be useful. What do Florence Nightingale and WHO, the World Health Organisation have in common?

### Wishball: hundreds

Test your understanding of place value with three-digit numbers. Start with a three-digit whole number such as 507. A spinner provides a randomly generated digit. Choose its place value and add it to (or subtract it from) your starting number. Work towards a given target number, say 539, using other digits. You can choose ...

### Wishball challenge: whole numbers

Test your understanding of decimal place value with whole numbers. Receive a starting number, such as 3786, and work towards turning it into a target number, 7664. Spin a random digit, choose its decimal place value and use the given operation (either addition or subtraction) on your starting number. Be careful not to overshoot ...

### Whole numbers level 5: four-digit numbers

This set of online activities focuses on the development and consolidation of number concepts to four digits and beyond. This is the fifth of seven levels in a series focusing on whole numbers to six digits. This level develops ideas about place value, rounding and number notation. Each level includes interactive drills ...

### Rounding decimals

This is a six-page HTML resource about solving problems concerning rounding. It contains one video and eight questions, four of which are interactive. The resource discusses and explains solving problems with rounding of decimals to reinforce students' understanding.

### Rounding decimals to the nearest tenth

This is a digital resource comprising a video demonstration of rounding a decimal fraction to the nearest tenth. The commentary uses and interchanges between the language of decimal places and decimal place values expressed in terms of tenths and hundredths. Practice questions dealing more broadly with rounding numbers ...

### The foul food maker: go figure

This tutorial is suitable for use with a screen reader. It explains how the use of simple words can describe the likelihood of everyday events. How likely is an event: certain, likely, equal chance, unlikely or certainly not? Answer some questions using these words and then build your own examples. Learn how to describe ...

### Wishball challenge: hundreds

Challenge your understanding of place value in whole numbers up to 999. Receive a starting number, such as 328, and work towards turning it into a target number, such as 177, within 20 turns. Spin a random digit, choose its decimal place value and use the given operation (either addition or subtraction) on your starting ...

### Wishball challenge: tens

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### Rounding whole numbers: 2

This is a video demonstration of rounding a whole number to the nearest thousand. In the commentary, the presenter explains the thinking behind the process of rounding such numbers and presents a visual representation of rounding whole numbers using a number line. Practice questions with answers are included, and hints ...

### Comparing fractions: strategies: assessment: teacher guide

Use this resource with 'Comparing fractions: strategies: assessment' (L9771). First, see a profile of that assessment object, which gives you some helpful background information. Then follow clear guidelines on the interpretation of student input related to comparing fractions and deciding which pair of fractions is larger, ...

### Bob Brown recalls the launch of the Blue Streak, 2006

This is an edited sound recording of Bob Brown recalling the excitement in Woomera in South Australia at the intended first launch of a Europa Blue Streak rocket from the nearby rocket range in June 1964. He tells how hundreds of families gathered to watch, only to be let down when the launch was cancelled with just seconds ...

### Ian Ritchie describes the launch of the Blue Streak, 2006

This is an edited sound recording of Ian Ritchie recalling the first launch of a Europa Blue Streak rocket from the Woomera rocket range in South Australia on 5 June 1964. Ritchie, an engine technician at the range, tells of the noise at lift-off and how the first flight of the rocket was cut short. The recording was made ...

### Comparing fractions: assessment: teacher guide

Use this resource with 'Comparing fractions: assessment' (L7736). First, see a profile of that assessment object, which gives you some helpful background information. Then follow clear guidelines on the interpretation of student input related to comparing fractions and deciding which pair of fractions is larger, or if they ...

### Andy Thomas describes his first flight into space, 2008

This is an edited sound recording of Australian astronaut Andy Thomas talking about his first flight into space in May 1996. Thomas describes the experience of taking off aboard the US space shuttle Endeavour, and how he was able to look down from space on the city of his birth, Adelaide, at night. He also describes how ...

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Fill orders in a cake shop. Match a fraction to parts of a cake. For example, identify the fraction of a cake remaining after it has had one quarter removed. Check your prediction by making the fraction and seeing what it looks like as part of a circle. Watch the circle change as you adjust the numerals in the numerator ...

### Divide it up: puppies

Use a dividing tool to make equal shares of biscuits and toys in a pet shop. For example, share 34 biscuits equally between 6 puppies. Predict how many items each puppy will get, or how many packets can be filled. Check your prediction. Decide what to do with any leftovers. Complete a sentence describing the number operations.